In 2016, the CISG Advisory Council celebrated its fifteenth anniversary. On this occasion, the current members of the CISG Advisory Council decided to publish a book containing all CISG Advisory Council related documents. For the first time, the original versions of all Opinions and Declarations, their annexes, and the text of the CISG are published in one book. This book is designed to facilitate the work on and with the CISG. It enables the reader in gaining an overview of the CISG Advisory Council's work of the last fifteen years. Furthermore, it contains an introductory paper on the Advisory Council itself, its unique approach and some historical background of the Opinions.