CliffsNotes was started by a [[Nebraska]] native named [[Clifton Hillegass]] in 1958. He was working at [[Nebraska Book Company]] of Lincoln, Nebraska, when he met Jack Cole, the co-owner of [[Coles (bookstore)|Coles]], a Toronto book business. Coles published a series of [[Canada|Canadian]] study guides called [[Coles Notes]], and sold Hillegass the U.S. rights to the guides.
Hillegass and his wife, Catherine, started the business in their basement at 511 Eastridge Drive in Lincoln, with sixteen [[William Shakespeare]] titles. By 1964 sales reached one million Notes annually. CliffsNotes now exist on hundreds of works. The term "Cliff's Notes" has now become a [[Generic trademark|proprietary eponym]] for similar products.
[[International Data Group|IDG Books]] purchased CliffsNotes in 1998 for $14,200,000. [[Wiley (publisher)|John Wiley & Sons]] acquired IDG Books (renamed Hungry Minds) in 2001. In 2011, CliffsNotes announced a joint venture with AOL and reality TV show producer [[Mark Burnett]] to introduce a series of 60-second [[video [[study guide]] surveys of literary works.<ref name=marketplace>{{Cite web|title=CliffsNotes Goes Digital|url=http://marketplace.publicradio.org/display/web/2011/03/10/pm-cliffsnotes-goes-digital//|accessdateaccess-date=2011-03-10|publisher=American Public Radio|archive-url=https://web.archive.org/web/20110727192539/http://marketplace.publicradio.org/display/web/2011/03/10/pm-cliffsnotes-goes-digital//|archive-date=2011-07-27|url-status=dead}}</ref> CliffsNotes was acquired by [[Houghton Mifflin Harcourt]] in 2012, and—according to the site's "About" page—"the brand lives on today as part of the global learning company, and its mission of changing lives by fostering passionate, curious learners".<ref name=about>{{citeCite web|title=About CliffsNotes|url=https://www.cliffsnotes.com/discover-about|website=CliffsNotes|accessdateaccess-date=20 June 2015}}</ref>
