Houghton Mifflin Harcourt Learning Technology, originally started as Riverdeep Interactive Learning, is a publishing house for educational online and CD-ROM products based in San Francisco, Boston and Dublin, Ireland. Founded in 1995, Riverdeep was principally the creation of the Irish ex-investment banker Barry O'Callaghan. O'Callaghan was Riverdeep's CEO and controlling shareholder. Riverdeep also acquired the companies Broderbund, The Learning Company and Edmark, and became a distributor for said companies.