From the reviews: "The reading is very easy and pleasant for the
non-mathematician, which is really noteworthy. The two chapters
enunciate the basic principles of the field, ... indicate connections
with other fields of mathematics and sketch the motivation behind the
various concepts which are introduced.... What is particularly pleasant
is the fact that the authors are quite successful in giving to the
reader the feeling behind the demonstrations which are sketched. Another
point to notice is the existence of an annotated extended bibliography
and a very complete index. This really enhances the value of this book
and puts it at the level of a particularly interesting reference tool. I
thus strongly recommend to buy this very interesting and stimulating
book." Journal de Physique