Not having read nearly enough of them myself my nominee is Scotland's Gift.
I was captivated from the start by Macdonald's description of his long trip to St. Andrews in 1872 at the age of sixteen. He described his journey via ocean liner to Ireland's west coast where he kissed the Blarney Stone and then by car and train to Dublin, Glasgow, Edinburgh and the final leg into St Andrew's by train which passed several holes of the Old Course as it made its way into town. The next day he was taken to Old Tom Morris' shop where he obtained 3-4 clubs, secured a locker in the shop and was introduced to the game on the Old Course. Add to that his descriptions of bringing the game to Chicago, starting the Chicago Golf Club and his quest for the ideal course, as well as its insights into the man himself, and it is a fascinating journey.
What are some of your nominees?
And the nominees are:
Scotland's Gift, C. B. Macdonald
Golf Has Never Failed Me, Donald Ross
Golf Courses of the British Isles, Bernard Darwin
Golf Course Architecture in America, George Thomas
Spirit of St. Andrews, Alistair MacKenzie
Swinging into Golf, Ernest Jones
The Links, Robert Hunter
The Architectural Side of Golf, Wethered and Simpson
British Golf Links, Horace Hutchinson
Concerning Golf, John Low
Some Essays on G.C.A., Harry Colt
Book of the Links, Martin Sutton