The challenges of photography book publishing are well known. Print runs are low, production costs are high, and bookstores and online retailers are pressing for discounts. The rule of thumb in the book industry is that the cost of producing the book equals 20 percent of the retail price. Depending on the number of images to be reproduced, paper stock and size, type of binding, and other factors that raise the cost of production, the publisher can either charge a prohibitively high price for the book, or find another way to defray its costs.
Via Mario Pires