Gabe Newell of Valve fame is one wise fellow – particularly when it comes to his day job: making games and running one of the best companies out there. Recently I’ve listened to a few interviews with him about nearly everything.
In a talk he gave to The LBJ School he reveals Valve does not have QA department but they do a ton of play testing. I also love how hat selling in TF2 was happening so quickly that it broke PayPal!
In December he sat down not once but twice (the second time with coworkers) with The Nerdist. Both interviews are worth listening to and can be found here.
The Valve handbook for new employees is referenced a bit in the Nerdist interviews and is worth looking through (PDF).
EDIT:
Here’s what Gabe said at the DCIE Summit: