Royalties: This is usually the longest section in the book contract, and describes the division of the money, provided the author hasn't written the book for a one-time payment in a work-for-hire arrangement. There's no real standard for domestic royalties, which is the most profitable segment of sales for most authors. It depends on the genre of the work and the publishing house. Ignoring super-star authors who write their own tickets, the best rate most writers can hope for is 15% of the cover price of trade hardcover books, with this percentage being achieved only after a certain number of copies have been sold. Many segments of the publishing industry have successfully changed that maximum to 15% of publisher net, which amounts to less than half the cover price. The lowest royalties I've heard of are less than 5% of net in genres like romance literature, where the publisher may even own the rights to the pen name under which the books are published.
It's common to set a number of steps with which the royalties escalate, setting a lower rate for the first 5,000 copies, a higher rate for the next 5,000, and only reaching the maximum rate after 10,000 or more copies have been sold