This concise and accessible book is the perfect introduction to Badiou's thought. Responding to Tarby's questions, Badiou takes us on a journey that interrogates and explores the four conditions of philosophy: politics, love, art and science. In all these domains, events occur that bring to light possibilities that were invisible or even unthinkable; they propose something to us. Everything then depends on how the possibility opened up by the event is grasped, elaborated and embedded in the world -- this is what Badiou calls a 'truth procedure'. The event creates a possibility but there then has to be an effort -- a group effort in the case of politics, an individual effort in the case of love or art -- for this possibility to become real and inscribed in the world. As he explains his thinking on politics, love, art and science, Badiou takes stock of his major works, reflects on their central themes and arguments and looks forward to the questions he plans to address in his future writings. The book concludes with a short introduction to Badiou's philosophy by Fabien Tarby. For anyone wishing to understand the work of one of the most widely read and influential philosophers writing today, this small book will be an indispensable guide.