It's Friday, Book Business Day. Let's poke around a little at the mega-publisher Houghton Mifflin Harcourt. Here is some background on the company. Headquarters is here (notice how an iPhone app is front and center on this homepage.) Look at their many divisions here. Their handsome online HMH Spring 2010 children's catalog is here (including Clarion and Harcourt, too, if you keep turning the pages.) So take a look around and get to know this corner of the book business just a bit better. Below are a book trailer and promo piece from HMH.