Here's a list of useful books about Japanese baseball (all written in English!):
Cromartie, Warren with Whiting, Robert - Slugging It Out In Japan (1991) Memoir of Cromartie's playing days with the Yomiuri Giants from 1984-90.
Engel, Gary - The Japanese Baseball Card Checklist And Price Guide (2012 - Vintage Edition; 2008 -7th Edition) Indispensable lists of cards
Fitts, Robert K - Banzai Babe Ruth (2012) Story of the 1934 US Tour of Japan and the birth of professional baseball in Japan
Fitts, Robert K - Remembering Japanese Baseball: An Oral History Of The Game (2005) Interviews with 25 former Japanese players and administrators. A lot of those interviewed were Americans who went to Japan to play but there's a couple interviews of Japanese players.
Fitts, Robert K - Wally Yonamine: The Man Who Changed Japanese Baseball (2008) Biography of Wally Yonamine, one of the first Americans to play in Japan following the war
Fitts, Robert K and Engel, Gary - Japanese Baseball Superstars (2001) Biographies of all Japanese Hall Of Fame and Meikyukai members through the 2000 season.
Gall, John and Engel, Gary - Sayonora Home Run! The Art Of The Japanese Baseball Card (2006) Colorful book showing old (pre-1970) Japanese baseball cards - menko, bromide, etc
Johnson, Daniel E - Japanese Baseball: A Statistical Handbook (1999) - Essentially an almanac listing final standings and statistics for each year of Japanese baseball from 1936 to 1997 (in the edition I have, I think Amazon is selling a later edition)
Obojski, Robert - The Rise Of Japanese Baseball Power (1975) One of the first Western books to deal with Japanese baseball. It contains a history of the game in Japan along with a lot of the business side of the game.
Oh, Sadaharu and Falkner, David - Sadaharu Oh: A Zen Way Of Baseball (1984) Autobiography of Sadaharu Oh
Pearce, Ralph M - From Asahi To Zebras: Japanese American Baseball in San Jose, California (2005) History of Japanese American amateur baseball in San Jose, California from the 1920's to the 1950's. Of special interest are games played in San Jose in 1935 by the touring Tokyo Giants.
Reaves, Joseph A - Taking In A Game: A History Of Baseball In Asia (2002) History of baseball in Japan, China, Taiwan, Korea and the Phillipines
Whiting, Robert - The Chrysanthemum And The Bat: Baseball Samurai Style (1977) If you've ever read "You Gotta Have Wa", this is more of the same, but set in the 1970's
Whiting, Robert - The Samurai Way Of Baseball (2004) (published in hardcover as "The Meaning Of Ichiro") More cultural collision between West and East in the 1990's and 2000's, including the experiences of Japanese in the majors
Whiting, Robert - You Gotta Have Wa (1989) Cultural collision between West and East using baseball as its context
I don't mean to give Mr. Whiting's books short shrift here by any means. All three of his books are wonderful and fascinating and are all worth reading. It's just difficult to come up with a single sentence for each that differentiates them from each other in any way other than time frame.