A People's History of the United States
by Howard Zinn

The Life and Times of Mexico
by Earl Shorris

The First World War
by John Keegan
(this one I read along with Great Battles of World War I by Anthony Livesey - for the graphics)

Anarchism and the Mexican Revolution: the Political Trials of Ricardo Flores Magon in the United States
by Colin MacLachlan

Crossing the Buffalo: the Zulu War of 1879
by Adrian Greaves