Greenhill SAVP announced it has invested in Flat World Knowledge ("Flat World"), a publisher of open source commercial textbooks. Greenhill SAVP partnered with Valhalla Partners and High Peaks Venture Partners on an $8M Series A financing. The company makes its books available as free web-hosted textbooks. It earns revenue and pays its authors royalties by providing students with options to purchase print-on-demand soft cover textbooks, audio textbooks, and self-print individual chapters. The company offers digital study aids like mp3 study guides, interactive web quizzes, and digital flashcards.