For an overview of the history of Japanese people in Berkeley, a good reference is "The Japanese American Experience: The Berkeley Legacy 1895-1995."
This was written by T. Robert Yamada, who was born in 1925 and passed away on June 23, 2004. He was a founder of the Berkeley Historical Society and the general manager of Books Unlimited Cooperative. The book was published by the Berkeley Historical Society in April 1995, and is available for sale there. See their website at http:\\www.berkeleyhistoricalsociety.org