I don't know how old he is but it seems like I grew up hearing A.W. Tozers name, although I am almost sure that isn't quite true.
His book (audio), The Pursuit of God is available free on the ChristianAudio.com store this month (July 2010). In order to download it, you need to (if you haven't already) create an account, then add the book to your shopping cart. At checkout, enter the coupon code they give you which will charge you the wonderful $0.00 amount!