CEO of publisher Houghton Mifflin resigns

NEW YORK, March 15 (Reuters) - The chief executive of privately owned educational publisher Houghton Mifflin Harcourt has resigned, a company spokesman confirmed on Tuesday.

Barry O'Callaghan, who assumed the CEO post in April 2009, will stay as senior advisor to the company. He will be replaced on an interim basis by Chief Financial Officer Michael Muldowney, spokesman Josef Blumenfeld said.

Houghton Mifflin, whose authors include Philip Roth and which also publishes the Curious George children's books, has been moving more into educational services, such as school district consulting and teacher development, Blumenfeld said.

News of the resignation was reported earlier by The Wall Street Journal. (Reporting by Lewis Krauskopf; Editing by Tim Dobbyn)