Students at The California State University will now be required to buy a $49 digital version of Principles of Biology instead of paper biology textbooks, which generally cost more than $100 each. Although major publishers have been investing in digital book development for years, the population of Cal State’s three campuses makes this one of the biggest deals yet for a book designed solely for computers, tablets and smartphones, according to The Financial Times. Students can print the book if they prefer and they own access to it for life. Vikram Savkar, director of Nature Publishing (part of Macmillan) told The Financial Times that the reduction in paper and printing costs is so large that digital books could improve profit margins, even at half the price. Not only is the book cheaper and lighter, the technology also allows teachers to monitor students progress as they read through the book.