Ronald Takaki, who made it his life’s work to rewrite American history to include Asian-Americans and other ethnic groups excluded from traditional accounts and who helped start the first doctoral program in ethnic studies in the United States, died Tuesday in his home in Berkeley, Calif. He was 70. The cause was suicide, said his son Troy. He battled multiple sclerosis for years. “He struggled, and then he gave up,” his son said. Mr. Takaki, whose Japanese grandfather immigrated to Hawaii in the 19th century and worked on a sugarcane plantation, became a leading scholar of ethnicity and multiculturalism in...