BOSTON--(BUSINESS WIRE)--Houghton Mifflin Harcourt (HMH) (NASDAQ: HMHC) today announced that it will release its second quarter 2015 financial and operating results on Thursday, August 6, 2015, before the market opens. At 8:30 a.m. EDT on Thursday, August 6, 2015, HMH will also host a conference call to discuss the results with its investors. The call will be webcast live at www.ir.hmhco.com. The following information is provided for investors who would like to participate: Toll Free: (844) 835