Houghton Mifflin Harcourt Buys Tribal Nova Posted on April 15, 2013February 2, 2019 by Dave McMahon Houghton Mifflin Harcourt has purchased the Montreal-based app developer Tribal Nova. Tribal Nova does excellent work– well played HMH! http://www.boston.com/businessupdates/2013/04/12/houghton-mifflin-harcourt-buys-firm-that-develops-digital-games-for-pre-schoolers/jR6vxhezahqeGSH52SaxWP/story.html