Unbiased is rough. Try these for a starter and see what you think:
-Swords Around A Throne by John Elting.
-A Military History and Atlas of the Napoleonic Wars by Vincent J. Esposito and John Elting.
-Napoleon's Great Adversary by Gunther Rothenberg.
-Yorck and the Era of Prussian Reform by Peter Paret.
-Imperial Bayonets by George Nafziger.
-With Eagles to Glory by Jack Gill.
-Tactics of the Russian Army in the Napoleonic Wars by Alexander and Yurii Zhmodikov.
-The Enlightened Soldier by Charles White.
-The Formative Influences, Theories, and Campaigns of the Archduke Carl of Austria by Lee Eysturlid.
-Any selection of memoirs and primary accounts by von Brandt, Caulaincourt, de Brack, Parquin, etc that give an excellent picture of the period.