Details on the Hachette Book Group's upcoming office move have come into focus. Deputy director of publicity Jimmy Franco told PW that the publisher, which is currently situated in the Time & Life Building at 51st St. and Sixth Ave., will move a few blocks south, to 237 Park Avenue (at 45th Street) in the second quarter of 2007. HBG, which has about 350 people in New York, will occupy the 15th and 16th floors of the building and the new phone numbers it announced this past summer for employees will be active there. HBG has been looking for a new home since it was sold by Time Warner to Hachette last year.