<br> [An] excellent book on field theory written from a modern standpoint and using a mathematical language (that of 'functional methods') appropriate to this standpoint. A superior text. Bellac's book surveys the whole field, but is particularly good on the physics of condensed matter. It is written in a very clear way. He covers a lot of ground, but in such a way that a beginning research student can learn about topics as diverse as the ising model, the renormalization group, path integral methods, and non-abelian gauge field theories. In fact, the earlier sections of the book should accessible to final-year undergraduates in theoretical physics. The book is well planned, carefully written, and pedagogically sound. -- <p><br> Good undergraduates, graduate students, teachers at different levels, and curious scientists are among the potential readers of this very interesting book. --Journal of Statistical Physics<p><br>