Johnson is one of the more honest historians of recent times.( though I don't agree with _everything_ he writes )
His "A history of the American People" is a one volume read , and "Modern Times" well worth a browse as well.
His History of the American People shows that he can misinterpret some rather important things. But his Modern Times and Birth of the Modern are pretty terrific reads. His History of England is a total bore, but methinks he knows what he is talking about in this article on Islam