The first book was Race and Culture. Migration and Cultures was second. Conquests and Cultures was third. Thomas Sowell was quite prolific. He has plenty of other books that are so well written that it is hard to understand why others do not mimic his style. Walter Williams did a top notch job writing about similar subjects. Note - Sowell is still alive but is retired. I see him on youtube frequently, but I do not know if he is presenting anything new.