Blaschke products are an important class of functions in analytic function theory in the unit disk, both because of their involvement in factorization theorems and their utility for the construction of examples. This book gathers the principal results about Blaschke products heretofore scattered in research papers over the past 70 years and provides an extensive bibliography of over 300 items. It is hoped that research workers in and students of function theory will find the book a useful guide and reference to the subject of Blaschke products.