Arguably, this is Alain Badiou’s most impactful work as the first tome in what he set out as a trilogy of works: Being and Event, Logics of Worlds,
Norris, Christopher. 2009. Badiou’s Being and Event: A Reader’s Guide
Roffe, Jon. 2006. Alain Badiou’s Being and Event. Cosmos and History.
Bowden, Sean. 2008. Alain Badiou: Problematics and the different senses of Being in Being and Event. Parrhesia.
John Protevi covered B&E in a lecture series in 2009. His lecture notes are here: Notes on Being and Event (Part 1),
Anyone wanting a serious engagement with B&E will want to ensure they review the basics of set theory. Set theory plays the role of conditioning the field of Badiou’s philosophy in B&E. The following link provides an in-depth account of set theory: Set Theory and the Foundations of Mathematics.