Perpetual Motion Machine.

Please contact us to reserve books in advance. We will hold books for ten days, pending payment. All orders should be prepaid. Payment may be made by personal check, money order, or PayPal. Institutions can be billed to suit their needs. Domestic orders are shipped via the U.S. Postal Service (Priority Mail) starting at $17.00 for the first book. Shipping cost may be slightly higher depending on weight of book and shipping destination. Media Mail shipping rate is also available: $7.00 for the first book and $2.00 for each additional. Overseas orders are billed at cost. Books may be returned within 10 days for whatever reason, provided their condition has not been altered. We request that you notify us in advance of returns.