It seems anyone today can start their own style and become a Grandmaster, and books and DVDs are all over the place from Master soandso and Master what'shisname.

Just what does Master and Grandmaster mean?

The best answer that I have found is this: one who teaches martial arts to beginners, is a teacher (various countries have their own word for "teacher"); one who teaches teachers is a Master, and one who teaches Masters is a Grandmaster.

I really like the idea of a Master being one who teaches...