WOW, someone from the "arts" community.
Mamet has written numerous plays and TV scripts and is, as you can read, an excellent word smith. As a director I've heard he can be rather harsh and the his books on acting aren't always to my liking. However, he just hit one out of the park and he now stands as a giant in my eyes.
I'd suffer whatever slings and arrows he might throw as a producer/director for the opportunity to have small part in one of his productions.
For those unfamiliar, he wrote Pulitzer winning play Glengarry Glen Ross, but also wrote the screen play for the Untouchables, Ronin, and Wag the Dog. On TV he wrote an episode of Hill Street Blues and directed The Unit for it's first couple of seasons.