Of the French ones, this one is a classic (I hesitate to say it's the classic, as I'm far from an expert on the period, and far less widely read on Napoléon than I am on the few last Bourbons and their time, but Castelot's 2 volumes are almost always mentionned when historians recommend books on Napoléon. The second one is the more read of the two volumes, by the way). It's from the Perrin publishing house, which is an excellent publisher of history. The collection at Perrin this one is from (the LAP) is in the more classic narrative style of the "great biographies", though, whereas their main collection and the other best known French publishers of biographies (Fallois, Fayard, Flammarion etc.) favour the more modern and more analytical approach (don't expect the analytical if very readable style/approach and the talent for synthesis of historian-biographers like Simone Bertière, Jean-Christian Petitfils etc., nor the dryer but savant approach of historians like Hildesheimer either (she's a specialist of Louis XIII and Richelieu, I just bought her new "Monsieur Descartes". Castelot's work is more "academic" (ie: in the conservative style of the Académie Française) in the vein of Troyat, at least for this duology.

I enjoyed it a lot at the time, it's a good introduction to the period, through its central player.

If you're looking for a good synthesis on the wars, or the diplomacy of the era, or a good analysis of the politics or the military aspects, it's really not the right book (it might well exist, but I'm not aware of a single book that cover all those aspects and succeeds at it). The 2-volume biography is a synthesis of Castelot's 10-volume work on Napoléon and his time, so his more in-depth analysis of everything else around Napoléon is not in this work.

I don't know if it's been published in the Tempus collection (Perrin's excellent paperback collection) - some volumes from their most prestigious Librairie Académique Perrin collection remain forever published in a bound edition only. At 50 Euro for the set, it seems to be the case for Castelot's Napoléon.