In this case, we're talking about the upcoming Halo book by Eric Nylund, Ghosts of Coral (or of Onyx, depending on who you believe), but actually about Nylund's first Halo outing, The Fall Of Reach, which according to an interview with Nylund at Firing Squad, Microsoft commissioned him to write in... you guessed it, seven weeks.

Kudos to reprobate who pointed out the interview in the HBO forum.