The Wall Street Journal of August 20,2010 carries a story about start up Inkling's introduction of "four full-length interactive college textbooks . . . designed specifically for Apple's iPad." The texts, from McGraw-Hill (no releated info was found on their site about this), are best sellers in economics, psychology, marketing and biology. An introductory offer has chapters selling, beginning Monday, August 23, for $2.99 and the books for $69.99. Prices will go up to $3.99 a chapter and to $79.99 for whole books after the introductory period lapses.