The USA in the 19th Century: 

J. M McPherson, Battle Cry of Freedom

D. M Potter with D. Fehrenbacher, The Impending Crisis 1846-61

A. Farmer, Civil War and Westward Expansion 1803,-1890

Tudors: 

Ian Mortimer, The Time Traveller’s Guide to Tudor England 

T. Penn, Winter King: The Dawn of Tudor England

Russia: 

O. Figes, A People's Tragedy: The Russian Revolution

Simon Sebag Montefiore, Saschenka (fiction)

Simon Sebag Montefiore, Young Stalin

Robert Service, Lenin