"This is a tremendous and wonderful book for novices and experts alike. It provides a lucid and insightful look into the empirical and conceptual problems handled so successfully by quantum theory. Ghirardi also leads us through the debates concerning the interpretation and meaning of this tantalizing and fascinating theory--debates in which he himself has been one of the major participants."--"This impressive book leads the lay reader to a real understanding of the problems of interpreting quantum mechanics. It is a well-balanced, indeed wise, book, which will stand the test of time as an intellectually responsible introduction to the field. It is also so far as I know the first book at its level to have chapters on the important topics of quantum cryptography and quantum computation."--