Payment should accompany order if you are a new customer. Current customers will be invoiced with payment due in 30 days. Institutions billed per their requirements. ALL ITEMS SUBJECT TO PRIOR SALE. Books fully returnable up to ten days after purchase with prior notification.. All credit cards accepted. Postage: $4.00 for first book, $1.75 for each thereafter for USPS media mail. Postage for larger books, international orders and priority mail quoted individually. Reciprocal 20% Dealer Discount. All books in at least Very Good Condition in Very Good Dust Jacket unless otherwise stated.