If you only expect one gift I would vote for "The History of old time Farm Implement Companies and the Wrenchs they issued" by PT Rathbone Vol I,II,and III
If you expect two gifts I would add Ken Copes American Wrench Makers 1830-1930 2nd Edition.
I would also recommend Schultz's "Wrenchs Antique and Unusual" but its out of print and available only in the secondary market.
I have some others but these are the ones I go to most often, Happy Hunting