Taiko by Eiji Yoshikawa is pretty good. It's about the life of Hideyoshi, who nearly united all of Japan before he died and Tokugawa took over. It's pretty fictionalized and reads like a novel, so you get a lot of the folk stories about Hideyoshi spun into full scenes, but the battles and political stuff mostly seem to be kosher, and you get a helping of cultural/societal elements. It's kind of the Romance of the Three Kingdoms for the period, but less dry.
It ends before the end of Hideyoshi's life, though, so you don't get the part about his Korean campaign or the Tokugawa takeover. I think it kind of assumes the reader knows about the latter, though, because it's heavy on the foreshadowing.
As for an actual history book, sorry, can't help. :'(
