According to textbook author Henry L. Roediger (and Wadsworth Publishing Company senior editor Vicki Knight), the used textbook market is illegitimate, and entirely to blame for the rising costs of textbooks. As methods of "dealing with this problem", he recommends making previous editions of textbooks obsolete, binding the textbook with other materials, and passing laws to prevent the sale of used books. The concept is not unlike the limited licensing approach for computer software, which places rigid restrictions on resale and reproduction. The intent is to make users understand that the content of any textbook is the intellectual property of the author and/or the publisher, and that as such, subject to copyright. Obviously, this idea is completely opposed to the millennia-old tradition of the sale of used books, and would make that entire industry illegal.