The Nature of the Universe

All items are guaranteed as described. If an item is not as described, it is returnable within seven days of receipt, unless other arrangements are made. Full refunds given only when items are received in the same condition in which they were sent. We require new customers to send payment with their order. Customers known to us will be invoiced with payment due in thirty days, unless prior arrangements are made. Institutions will be billed to meet their requirements. All items subject to prior sale. We accept Visa, Mastercard, and American Express Please be advised that we can only ship to your billing address. We accept checks, but may require that the check clears before we ship an order. Prices of books do not include shipping. We use UPS domestically and internationally. Other shipping arrangements can be made. Shipping is always charged at cost. Texas residents must add 8.25% sales tax.