However, in March, one of the largest U.S. publishers, Random House, suddenly increased its library pricing for e-books by as much as 300%.

CNN: E-book lending: Your public library's best kept secret?

Of the six largest publishers in the U.S., only two have full-fledged library e-book lending programs: HarperCollins and Random House.

FORBES: What Is Going On With Library E-Book Lending?

Random House is the only major publisher to make e-books of its entire catalog available to any public library for unrestricted lending.

CNN: E-book lending: Your public library's best kept secret?