Just a note on hardcover vs. paperback (in response to John). The
difference in production cost between the two is utterly negligible
(ask any honest publisher). Hardcover books cost more because
people are willing to pay more for them, and perhaps also because
students can get more when they resell them and hence there is a
larger volume of used book sales. In other words, publishing a
book in paperback is rather like designing a car to fall apart
as quickly as possible so people will buy more new cars.