Verification of arms control may be arcane to some, but to others it is the most critical dimension of any agreement. This work is a most valuable contribution, bringing together for the first time the surprising amount of unclassified, yet hidden, information on the problem. The reader will learn much about American and, to a lesser extent, Soviet capabilities and perspectives on verification; the book has lasting value and is no less significant because of the present SALT deadlock. Verification, we are reminded, is as much art and politics as science. Disagreements abound here as in other dimensions of the strategic arms debate.