I just ordered The Meaning of the 21st Century by James Martin and am looking to back it up with some history on colonialism. What are some concise histories of that period?
"King Leopold's Ghost" by Adam Hochschild offers a fantastic history of the Belgian colonization of the Congo. I highly reccomend this as I used it while writing a research paper over Joseph Conrad's "Heart of Darkness" and it was a great supplement.
Another suggestion is "Africa: A Biography of a Continent" by John Reader. While this is a general history of Africa as a whole, it has a large section dedicated to colonization, and it's effect on modern day Africa.
D.K. Fieldhouse's Western Imperialism in the Middle East, 1914-1958 is quite good.