Book: The Making of Templar
I somehow missed The Making of Templar, a free ebook by Jordan Mechner, LeUyen Pham, and Alex Puvilland.
Jordan Mechner is best known as the creator of great games like Karateka (1984), Prince of Persia (1989), The Last Express (1997)... Most of these games are now available for modern platforms like iOS and Android.
You can download the free ebook from Jordan Mechner's page.