What the Buddha Taught Rahula, W.
Because, as a phil. student and buddhist practitioner (tantra-dzogchen who wants to be a scholar in indian studies), consider this book to be one of the best introductory books to buddhism that I’ve ever read. It is precise, concise, very clear exopsition of the main points, a very good relation with western concepts. Also, it is very clear about the non existence of god, the soul, etc. It gives a very good panoramic view of the main cycle of teachings, the different yanas, without falling in the classical mistake of considering Theravada = Hinayana (which is a horrible historical mistake to do so!).