Anders Bengtsson 
Interactions [PDF ebook] 

This book is an introduction to the theory of interacting higher spin gauge fields. It describes in a pedagogical way the methods used, and the results obtained, within the three major approaches to the subject: the Dirac light-front theory, the Fronsdal covariant approach and the Vasiliev Ad S theory. Abstract concepts and methods unifying the various appproaches are pointed out. The book follows the ideas behind the first volume; explains the mathematical concepts and tools used, while also reviewing the history of the subject.