Badiou's book collects eulogies to certain recent-contemporary giants of French intellectual life. All are beautifully written, most shed light on Badiou's own philosophy, and some are excellent introductions to their subject matters.
The eulogy to Derrida is probably the best in the collection, precisely for how it combines humour, clarity and sympathy in its reconstruction - I hope you'll pardon me here - of deconstruction. Also particularly notable are the entries on Sartre, Althusser and Lyotard. The impression is reinforced that for Badiou, there are no problems of a strictly or abstractly philosophical importance; for a philosophical "interventionist", in a constrained but important sense the philosophical is the concrete. This accounts for his rooting of interpersonal sympathies and dissonances at a level of abstraction that is often surprising and counter-intuitive. Through humour, sadness, love and ire, the force of Badiou's personality shines through in virtually every eulogy, giving body to the austere rigour of his own philosophical work.
Though highly interesting, the book is more for browsing than reading cover to cover, a supplement to one's studies at best. For example, the discussion on the Kantianism/Spinozism of Francoise Proust means nothing to me at this point; as a North-American student of French theory, there's a fair bit regarding more minor personalities that eludes my grasp. The main attraction for me was the prospect of reading Badiou on his philosophical contemporaries, both allies and rivals. I was rewarded with the usual aesthetic experience of his writings, but also a clearer picture of his self understanding vis a vis French intellectual life. I hesitate however to recommend this text for systematic study. If you're curious about, say, Sartre's influence on Badiou, by all means turn to the essay in this book. We must, however, pick our battles.