There are so many good books you need to read e.g.
"100 Jahre Jiu-Jitsu /Ju-Jutsu und Judo in Deutschland : Eine Chronik von 1905-2005" by Velte, Herbert (1935 - ), Matschke, Klaus Dietrich, Vierkirchen, Germany, Schramm Sport, 2005, 164p, ISBN 3000161309
"100 Years of Judo in Great Britain: No. 1: Reclaiming of Its True Spirit" by Bowen, Richard (Dickie) (1926 – 2005), London, United Kingdom, IndePenPress Publishing Ltd, 2011, 428p, ISBN13 9781907499319
"100 Years of Judo in Great Britain: No. 2: Reclaiming of Its True Spirit" by Bowen, Richard (Dickie) (1926 – 2005), London, United Kingdom, IndePenPress Publishing Ltd, 2011, 506p, ISBN13 9781780030104
"2000 Years : Jujitsu and Kodokan Judo" by Helm, Dennis, Illinois, United States, Illinois Judo association, 1991, 116p,
"2004 olympic games Judo" by Essen, Hans van, Nieuwegein, Netherlands, Infostrada sport, 2004, 294p,
"30 godina Judo kluba Jaska" by Vuković-Cena, Zdenko, Jastrebarsko, Croatia, Judo klub Jaska, 2010, 248p, ISBN13 9789535639909
"50 great Judo champions" by Hicks, Simon, Soames, Nicolas (1950 - ), London, United Kingdom, Ippon Books, 2001, 117p, ISBN 1874572917
"50 Jahre Schweizerischer Judo- und Ju-Jitsu-Verband : 50 ans Association Suisse de Judo et Ju-Jitsu 1937 - 1987 , UA, , Zurich, Switzerland, SJV AJS, 1987, 48p,
"50 lat polskiego judo wymiar olimpijski" by Sikorski, Waldemar, Lodz, Poland, Wydawnictwo Wyzszej Szkoly Humanistyczno-Ekonomicznej w Lodzi, 2009, 222p, ISBN13 9788374054553
"70 Jaar Judo Bond Nederland : Vechten. Besturen. Verenigen." by Evers, Frans, Hell, Jos ; Koeman, Wouter ; Liempdt, Jos Van ; Vries, Martin de, Rotterdam, Netherlands, Bookexpress.info, 2010, 280p, ISBN13 9789077850107
"A bibliography of judo and other self-defense systems including cognate works and articles" by Smith, Robert William (1926 - 2011), Rutland, Vermont, United States, Charles E. Tuttle, 1959 1961, 249p,
"A complete guide to Judo : It's story and practice" by Smith, Robert William (1926 - 2011), Rutland, Vermont , United States, Charles E. Tuttle, 1958[1] 1959[1] 1960[1], 249p,
"A History of Judo" by Hoare, Sydney R. (1939 - ), UL, United Kingdom, Yamagi Books, 2008, 160p, ISBN13 9780956049803
"A magyar judosport fél évszázada" by Sági, József, Budapest, Hungary, Magyar Judo Szövetség, 2004, 295p,
"A perfect manhood or, Judo of Kodokwan" by Steers, William E., London, United Kingdom, The Budokwai, 1918, 12p,
"Alfred Rhode : Ein Leben für den Judosport" by Velte, Herbert (1935 - ), Bruckmühl, Germany, Sensei, 1997, 100p, ISBN 3923473567
"Asian fighting arts" by Draeger, Donn F. (1922 - 1982), Smith, Robert William (1926 - 2011), London, United Kingdom, Ward Lock, 1969, 207p, ISBN 0706317998
"Association de judo & ju-jitsu Valais, 1961-2011 = Walliser Judo und Ju-Jitsu Verband, 1961-2011, Cerigioni, Claudio, Curty, Marc, Sierre, Switzerland, Ed. Impr. Calligraphy, 2011, 94p,
"Bibliographical notes on some scientific works about judo and jiu-jitsu" by Salling, Kjell, Sarpsborg, Norway, by Author, 1983, 28p,
"Choque: The Untold Story of Jiu-Jitsu in Brazil 1856-1949 (Volume 1) " by Pedreira, Roberto, UL, United States, GTR Publications, 2014, 744p, ISBN13 9781491226360
"Classical fighting arts of Japan : a complete quide to Koyrū Jūjutsu" by Mol, Serge (1970 - ), Tokyo, Japan, Kodansha International, 2001, 242p, ISBN 4770026196
"Conde Koma : O invencível yondan da história" by Virgílio, Stanlei, Campinas, SP, Brazil, Editora Átomo, 2002, 105p, ISBN 858758524X
"Écrits de judo" by Lamendin, Henri (1928 - ), Guillestre, France, Souvenirs éd, 2007, 152p, ISBN13 9782952868525
"Eesti Judo 40 " by Lääne, Tiit, Esna, Kati ; Meijel, Toni ; Pohjala, Aavo ; Rannikmaa, Riho ; Lume, Tõnu, Tallinn, Estonia, Tallinna Raamatutrükikoda, 2010, 232p, ISBN13 9789949211654
"El judo : Historia, evolución en España" by Benítez, Salvador, de Aragón, Madrid, Spain, Imperia Fernando Franco, 1959, 80p,
"El judo alcoyano : treinta años con el deporte" by Peidro, Luís, Payá, Alcoi, Spain, Judo Club Alcoi, 1995, 91p,
"El judo en Cuba" by Mayo, José, Habana, Cuba, Edit. Científico-Técnicna, 1985, 139p,
"El judo en la Argentina : método teórico práctico editado en la República Argentina para toda la América Latina" by Cosentino, Antonio, Buenos Aires, Argentina, Talleres Graficos de la Prision Nacional, 1943, 82p,
"El Judo en Venezuela" by Herrera, Hector, Linarez, Ali, Barquismieto, Venezuela, Instituto Universitario Expermental de Tecnologia/Andres Eloy Blanco, 2001, 154p, ISBN 9803490044
"Entretiens avec les pionniers du judo français" by Thibault, Claude (1934 - ), Paris, France, Résidence, 2000, 286p, ISBN 2912640067
"Erwin von Baelz und die körperlichen Übungen : Leibeserziehung und traditionelle Kampfkünste im Japan der Meiji-Zeit" by Bittmann, Heiko, Ludwigsburg, Germany, Verlag Heiko Bittmann, 2010, 174p, ISBN13 9783980731645
"Fighting Spirit: Judo in Southern California, 1930-1941" by Uchima, Ansho Mas , Kobyashi, Larry Akira, Pasadena, California, United States, Midori Books, 2006, 433p, ISBN 0974969710
"Getting a grip : judo in the Japanese American communities of Washington and Oregon, 1900-1950" by Svinth, Joseph R. (1957 - ), Seattle, Washington, United States, J. R. Svinth, 1998, 225p,
"Great Judo championships of the world" by Yeoh, Oon Oon, London, United Kingdom, Ippon Books, 1993, 240p, ISBN 1874572208
"Histoire du Ju Jutsu" by Gouedard, Philippe, UL, United States, lulu.com , 2012, 90p, ISBN13 9781291161090
"Histoire du Judo (Revue Judo Kodokan nº 5, vol. XII, 1962)" by Kodokan, , Paris, France, Federation International de Judo, 1962, 160p,
"Histoire du judo en Franche-Comté" by Vial, Frédéric, Ruffin, François, Franois, France, Empreinte, 2000, 182p, ISBN 2913489168
"Historia del Judo Argentino : Tomo 1" by Uequin, Juan Carlos, Buenos Aires, Argentina, Editorial kier, 2005, 223p, ISBN 9501755177
"Historia del Judo en Cuba 1951-1961" by Flores Pérez, Abelardo (1938 - 2005), Flores Pérez, Fernando (1936 - ) ; Guzmán Gómez, Ernesto (1972 - ), Habana, Cuba, Editorial Científico Técnico, 2007, 244p,
"History of Oxford & Cambridge University judo" by Green, Tim, Godalming, United Kingdom, T. Green, 1987, 15p,
"Introducción al Judo" by Vilamón, Miguel, Brousse, Michel (1952 - ) ; Molina, J. Pere, Barcelona, Spain, Hispano Europea, 1999, 351p, ISBN 8425512964
"Introducción y desarrollo del judo en España : (de principios del siglo XX a 1965) : el proceso de implantación de un método educativo y de combate importado de Japón" by Gutiérrez, Carlos, García, Léon, Spain, Universidad de Léon, Secretariado de Publicaciones y Medios Audiovisuales, 2004, 493p, ISBN13 9788497730648
"Ippon! The fight for judo’s soul" by Hammond, Dave, London, United Kingdom, London League Publications Ltd, 2008, 86p, ISBN13 9781903659380
"Jigoro Kano : Père du judo" by Mazac, Michel, Noisy-sur-École, France, Budo éditions, 2006, 316p, ISBN 2846171106
"Jigoro Kano, Un Grand Initie : Symbolisme et Philosophie du Judo" by Lepage, Claude (1927 - ), Nantes, France, Amalthee, 2008, 271p, ISBN13 9782310000642
"Joustavan tien kulkijat : puoli vuosisataa suomalaista judoa" by Marttila, Jouko T., Helsinki, Finland, Suomen Judoliitto, 2008, 155p, ISBN13 9789529246410
"Judo : A sport and a way of life" by Brousse, Michel (1952 - ), Matsumoto, David, Seoul, Korea, International Judo Federation, 1999, 165p,
"Judo : official results book = Judo : brochure des résultats officiels (Games of the XXVII Olympiad = Les Jeux de la XXVII Olympiade)" by International Olympic Committee, , Lausanne, Switzerland, International Olympic Committee, 2000, 80p,
"Judo : the athletes of the summer games" by Lyberg, Wolf, Stockholm, Sweden, W. Lyberg, 1996, [37] f. ,
"Judo : top action" by Klocke, Ulrich (1948 - ), Oxford , United Kingdom, Meyer & Meyer, 2001, 167p, ISBN 1841260355
"Judo : Webster's Timeline History, 1708 - 2007" by UA, , UL, United States, Icon Group International, 2009, 68p,
"Judo Champion" by Archer, Eleanor, London, United Kingdom, Franklin Watts, 2000 2004, 24p, ISBN 0749636653
"Judo Champion" by Briggs, Karen (1963 - ), Soames, Nicholas (1950 - ), Marlborough, United Kingdom, Crowood, 1988, 160p, ISBN 1852231033
"Judo in the United States : a century of dedication" by Brousse, Michel (1952 - ), Matsumoto, David, Berkeley, CA, United States, North Atlantic Books, 2005, 158p, ISBN 1556435630
"Judo jiu-jitsu and hand-to-hand fighting a list of references" by Jones, Helen Dudenbostel, Washington, United States, Library of Congress, 1943, 18p,
"Judo mistrzów" by Pawluk, Janusz, Warszawa, Poland, Sport i Turystyka, 1975 1981[2], 124p,
"Judo, Budo et tradition : la voie et ses degrés" by Wirz, Bernard, Lausanne, Switzerland, Hagakuré, 2005, 254p, ISBN 283990117X
"Judo-jujitsu en Auvergne : 1949-1999, cinquantième anniversaire : son histoire au pays des volcans... résultats sportifs interrégionaux, nationaux et internationaux" by Gazet, Laurent Joseph (1927 - ), Clermont-Ferrand, France, L. J. Gazet, 1999, 190p, ISBN 2951375700
"Judoka : the history of judo in Canada" by Leyshon, Glynn A. (1929 - ), Gloucester, Ont., Canada, Judo Canada, 1997, 188p, ISBN 1894165004
"Judokan käsikirja" by Kivinen, Jorma, Lappeenranta, Finland, Suomen dan-kollegio, 1986, 191p, ISBN 9519970657
"Judokas et dojos de Haute-Alsace : 1945-2005, soixante ans d'histoire" by Muckensturm, Michel (1953 - ), Briswalter, Georges ; Guillocheau, Guy, Mulhouse, France, Comité du Haut-Rhin de Judo, 2005, 301p, ISBN 2952553602
"Judon historia" by Kyllönen, Ari, Kuopio, Finland, Ari Kyllönen, 2003, 141p, ISBN 9518422648
"Jujutsu and judo : what are they?" by Kanō, Jigorō (1860 - 1938), Tokyo, Japan, Kodokwan, 1937, 70p,
"Jujutsuns väg : från självförsvar till idrott" by Malmstedt, Jan (1939 - ), Nobok, Sweden, Informationsförlaget, 1995, 160p, ISBN 9177363736
"Junomichi - L'origine du judo : entretiens avec Igor Correa" by Correa, Igor (1919 - 2000), Hanneur, Loïc Le ; Stéfano, Rudolf Di (1970 - ) ; Bruel, Laurent (1970 - ), Noisy-sur-École, France, Budo éditions, 2010, 207p, ISBN13 9782846172738
"Kampfwürfe und Kampfaktionen : ein Judo-Fotoband : Angriff und Verteidigung, Kombinationen und Gegenwürfe, Spezialtechniken und allgemeine Kampfaktionen, vorgeführt von japanischen, europäischen sowie deutschen Judo-Meistern und anderen : auf Einzel- und Reihenbildern" by Velte, Herbert (1935 - ), Esser, Fritz-Albert, Bad Homburg, Germany, Budo-Artikel-Vertrieb, 1974, 48p,
"Kamppailijoita dojolta tatamilta" by Laaksonen, Tero, Helsinki, Finland, by Author, 1992, 195p, ISBN 9529037775
"Kichisaburo Sasaki - Raccolta fotografica" by Marzagalli, Marco, Milano, Italy, La Comune, 2009, 70p, ISBN13 9788896302125
"La vie d'un champion : Cours de culture physique et de jiu-jitsiu" by Vaucher, Abel, Cherpillod, Armand (1876 - ), Lausanne, France, Civis, 1933, 307p,
"L'aventure du judo francais" by Quidet, Christian, Paris, France, Solar, 1973, 187p,
"L'avventura del Judo" by Barioli, César (1935 - ), Milano, Italy, Vallardi, 2004, 224p, ISBN 8876963685
"Le Judo" by Hansenne, Marcel (1917 - ), Paris, France, La Table Ronde, 1962, 247p,
"Le judo : son histoire ses succès" by Brousse, Michel (1952 - ), Genève, France, Liber, 1996, 187p, ISBN 2881430775
"Le Judo, quelle histoire : des samouraïs aux jeux Olympiques" by Fradet, Claude, Cergy Pontoise, France, SFM Noris, 1997, 152p, ISBN 2906823092
"Le Palmarès du judo français" by Damie, Jean Philippe, Choisy-le-Roi, France, CES [Conseil en équipements sportifs], 1990, 255p, ISBN 2950444717
"Leben und Werk Kanô Jigôros (1860 - 1938): Ein Forschungsbeitrag zur Leibeserziehung und zum Sport in Japan" by Niehaus, Andreas, Würzburg, Germany, ERGON, 2003, 382p, ISBN 3899133102
"Les 3 maîtres du budo : Jigoro Kano (judo), Morihei Ueshiba (aïkido), Gishin Funakoshi (karatedo)" by Stevens, John (1947 - ), Reymond, Philippe (1918 - ), Noisy-sur-École, France, Budo, 1997, 127p, ISBN 2908580705
"Les pionniers du judo français" by Thibault, Claude (1934 - ), Paris, France, Budo Editions, 2011, 496, ISBN13 9782846172813
"Les racines du judo francais : Histoire d'une culture sportive" by Brousse, Michel (1952 - ), Bordeaux, France, Presses Universitaires de Bordeaux, 2006, 367p, ISBN 2867813689
"Les trois maîtres du budo : Jigorô Kanô, jûdô, Morihei Ueshiba, aikidô, Gichin Funakoshi, karate-dô" by Stevens, John (1947 - ), Reymond, Philippe (1918 - ), Noisy-sur-École, France, Budo, 2006, 123p, ISBN13 9782846171144
"Lion aroused : Conversations with Shigeyoshi Matsumae" by Sakamoto, Mamouru, Tokyo, Japan, Tokai University press, 1986, 298p,
"L'origine du judo : entretiens avec Rudolf di Stefano et Laurent Bruel" by Correa, Igor (1919 - 2000), Montreuil, France, Association des actions physiques et mentales, 2002, 159p, ISBN 2847670009
"Making a Champion in the Right Time for Gold : Championship Judo" by Mullen, Eddie (1949 - ), Bloomington, Indiana, United States, AuthorHouse, 2007, 196p, ISBN13 9781434300836
"Manuals on mayhem" by Steiner, Bradley J., Mason, Michigan, United States, Loompanics, 1979, 86p,
"Martial Arts in the Modern World" by Green, Thomas A. (1949 - ), Svinth, Joseph S., Westport, CT, United States, Praeger Publishing, 2003, 322p, ISBN 0275981533
"Mulheres do Tatame - o Judô Feminino no Brasil" by Souza, Gabriela Conceição de, Mourão, Ludmila, Rio de Janeiro, Brazil, Mauad editora LTd, 2011, 28p, ISBN13 9788574783727
"My turbulent life in a turbulent century" by Matsumae, Shigeyoshi (1901 - ), Tokyo, Japan, Tokai University press, 1982, 241p,
"Nakada : Een Haagse Jiu-Jitsu en Judo school in woord en beeld" by Smits, Johan H. G., UL, United Kingdom, lulu.com, 2009, 108p, ISBN13 9789090239538
"Never look back : the Owen Lowery story" by Harley, V. G., Crowborough, United Kingdom, Highland, 1990, 224p,
"O pai da educação integral e o universo do judô" by Suzuki, Eico, Sao Paulo, Brazil, Editora do Escritor : Luz e Silva Editor, 1986, 72p,
"O que É Judô : História, Regras, Curiosidades" by Vieira, Silvia (1967 - ), Freitas, Armando, Rio de Janeiro, Brazil, Casa da Palvra, 2007, 93p, ISBN13 9788577340194
"Olympic judo : history and techniques" by Soames, Nicolas (1950 - ), Inman, Roy (1947 - ), Aylesbury, United Kingdom, Crowood, 1990, 253p, ISBN 185223489X
"Origen del Judo Panamericano" by Guardia, Luis, Miami, FL, United States, Eagle Press, 2011, 240p, ISBN13 9780984145225
"Origins of Pan-American Judo" by Guardia, Luis, Garcia, Benito, Miami, FL, United States, Eagle Press, 2012, 240p, ISBN13 9780984145270
"Painin Historia" by Lehmusto, Heikki, Helsinki, Finland, Otava, 1920, 343p,
"Painin Historia" by Lehmusto, Heikki, Helsinki, Finland, Otava, 1939[2], 487p,
"Painiskeluopas" by Lehmusto, Heikki, Laitinen, Armas, Helsinki, Finland, Otava, 1924, 182p,
"Personagens e histórias do judô brasileiro" by Virgílio, Stanlei, Campinas, SP, Brazil, Átomo , 2002, 299p, ISBN 8587585274
"Ren-sei-kan : Meio século de Judo" by Ueda, Takeshi, Vaccari, Enir, Rio de Janeiro, Brazil, Zit Editions, 2004, 91p, ISBN 8589907015
"Saving Japan's Martial Arts" by Clarke, Christopher M., Seattle, United States, CreateSpace Independent Publishing Platform, 2013, 282p, ISBN13 9781466211728
"Storia del Giappone e nascita del Judo" by Marzagalli, Marco, Milano, Italy, La Comune, 2009[1] 2010[2], 88p, ISBN13 9788896302033
"Suomalaisen judon historiaa : Wolfgang Dhuy" by Kyllönen, Ari, Kuopio, Finland, Ari Kyllönen, 2005, 18p, ISBN 9518422915
"Svenska judoförbundets 40-års jubileumsskrift" by Svenska judoförbund, , Farsta, Sweden, Svenska judoförbund, 2000, 39p,
"The development of judo in Britain : a sociological study" by Goodger, Brian Christopher, London, United Kingdom, University of London, 1981, 441p,
"The Discovery of Judo, Yield to Overcome" by Désormeaux, Ronald (1941 - ), Ottawa, Canada, Scribd.com, 2006 2009[2], 123p, ISBN 2980626902
"The History of Jon Bluming : From Street Punk to 10th Dan" by Bluming, Jon (1933 - ), Amsterdam, Netherlands, Jon Bluming, 2000, 160p,
"The Judo Twins" by Friedland, Stan" by Bloomington, Indiana, United States, AuthorHouse, 2007, 333p, ISBN 1434341798
"The life and struggles of a fighter for peace : Shigeyoshi Matsumae's contribution to histrory" by Shirai, Hisaya, Tokyo, Japan, Tokai University press, 1988, 371p,
"The Original Martial Arts Encyclopedia : Tradition-History-Pioneers" by Cocoran, John, Farkas, Emil, Los Angeles, United States, Pro-Action Publishing, 1993, 436p, ISBN 0961512636
"The toughest man who ever lived" by Murray, John (1932 - ), Bunasawa, Nori, Irvine, CA, United States, Judo Journal, 2003[1] 2007[2], 296p, ISBN 096489842X
"The Way of Judo: A Portrait of Jigoro Kano and His Students" by Stevens, John (1947 - ), Boston, United States, Shambhala, 2013, 225p, ISBN13 9781590309162
"Three budo masters : Jigoro Kano (judo), Gichin Funakoshi (karate), Morihei Ueshiba (Aikido)" by Stevens, John (1947 - ), Tokyo, Japan, Kodansha International, 1995, 144p, ISBN 4770018525
"Tout le judo : histoire, technique, philosophie, anecdotes" by Godet, Robert J., Paris, France, Amiot-Dumont, 1952, 177p,
"Trzej mistrzowie budo : Jigoro Kano (judo), Gichin Funakoshi (karate), Morihei Ueshiba (aikido)" by Stevens, John (1947 - ), Bydgoszcz, Poland, Diamond Books, 2001, 143p,
"Uma interpretação histórico-filosófica do judo" by Viana, Mário Gonçalves (1900 - 1977), Lisboa, Portugal, Sep. do Bol. do Inst. Nac. de Educação Física, 1954, 29p,
"Un million de judokas : histoire du judo francais" by Thibault, Claude (1934 - ), Paris, France, Editions Albin Michel, 1966, 270p,
"Wrocławskie judo" by Wojno, Adam (1943 - ), Wrocław, Poland, Agencja Ochronna Budo, 1999, 151p, ISBN 8391187403
But seriously I'd start from Niehaus and Brousse.