NATO's decision to open itself to new members and new missions is one of the most contentious and least understood issues of the post-Cold War world. This book, an unusual and intriguing blend of memoirs and scholarship, takes us back to the decade when those momentous decisions were made. Former senior officials from the United States, Russia, Western and Eastern Europe who were directly involved in the decisions of that time describe their considerations, concerns, and pressures. They are joined by scholars who have been able to draw on newly declassified archival sources to revisit NATO's evolving role in the 1990s.