The author publishes and freely distributes three online textbooks. "Introduction to Physical Oceanography" is available as a typeset book in Portable Document Format (PDF) or as web pages. "Our Ocean Planet: Oceanography in the 21st Century" and "Environmental Science in the 21st Century" are both available as web pages. All three books, which can be accessed from the Ocean World website (http://ocean world.tamu.edu/index.html), are widely used by professors and students throughout the world. The "Physical Oceanography" textbook has become especially popular and has been translated into Portuguese and Italian and partly into Russian. Thus, the author is frequently asked why he makes his textbooks available for free and why he avoided the traditional route to publication through commercial publishers, thereby giving up the royalties he could have earned from printed textbooks. In this article, the author explains his answers to this question. (Contains 1 note.)