Joe Tessitore, president of HarperCollins’ reference group, Collins, will leave the company by the fall. According to the memo from HC president Brian Murray, Tessitore will retire from fulltime publishing by November 1. Tessitore joined HC in late 2004 and shortly after his arrival was put in charge of combining a number of separate HC divisions to form a new unified reference group. The Collins division officially launched in fall 2005 and has had several big hits, including, You: The Owners Manual. Tessitore also negotiated a co-publishing agreement with the Smithsonian Institution. It was unclear when Tessitore will leave HC. In his memo, Murray said Tessitore "will continue to work with Collins to facilitate a smooth transition while we begin searching for a successor." Prior to joining HC, Tessitore was publisher of PW and had served as president of Grolier/Scholastic.