Napoleon the Great Andrew Roberts
Napoleon Adam Zamoyski
(The latest and arguably one of the best one volume biographies)
The Age of Napoleon Alistair Horne
Napoleon 1815-40 Philip Dwyer
Any of the Osprey published military history books, eg Jena 1806 by David Chandler
Waterloo Andrew Roberts (best short introduction)
Napoleon: A Life in Gardens and Shadows Ruth Scurr
(The author is an acknowledged expert on The French Revolution - This book is offbeat and wonderful. I find her writing quite addictive)
Comments