"The Spirit of St. Andrews" by MacKenzie, incorporating as it does that little gem, "Golf Architecture."
"Golf Courses of the British Isles" by Bernard Darwin. Amazing how real life it is today, plus introducing the verb, "to foozle," and noun, "foozler."
"Evangelist of Golf," by George Bahto, and C.B. MacDonald's "Scotland's Gift, Golf," which are companion volumes.
"Alister MacKenzie's Cypress Point," by Geoff Shackleford, if for nothing else but MacKenzie and his Packard on the pristine fairways. The black and white photos are marvelous.
Doak's "Anatomy of a Golf Course," which taught me golf course construction's details more than any other text. "Driving the Green" by John Strawn was my first golf architecture book and is a close second in many ways.
My latest addition, and very informative and interesting, is Forrest Richardson and Mark Fine's book on hazards. Good stuff.
Is there another sport with the wealth of literature of golf? I love to pull out the Herbert Warren Wind and the Darwin and a recently acquired copy of Henry Longhurst's biography. And P.G. Wodehouse, what more can you say?