Introductory deal: Choose three books on astronomy, physics, geometry, math, space and many other scientific topics for $1.99 each plus $14.99 shipping and handling (total = $20.96) when you join the Scientific American Book Club. Then: Purchase one more selection from the club catalog within a year at up to 50 percent off publisher prices (prices start at $12.95). Categories: Astronomy, Biology, Chemistry, Computers and Technology, Earth and the Environment, Evolution and Paleontology, General Science, Mathematics, Physics. Shipping & handling: $6.49 for the first book in an order, $3.99 for each of the second and third, $1.99 for the fourth and no charge for any additional. Catalog arrives: Every three weeks. Order / decline online?: Yes. Return days: 20 on introductory offer; 15 otherwise. Credit card required? Yes. Sales tax: Indiana, New York, Pennsylvania Customer service: Email. Open to: U.S. residents, including its territories and APO/FPO.