|Occupation||Formerly Lance Private of the castle guard, future doctor|
|Physical appearance||Smart and clean|
|Books||I Shall Wear Midnight|
Preston is a young castle guard (under the new Baron Roland) who is perhaps too clever for his own good. So clever, in fact, that he will play dumb in situations where large words would be unappreciated and unhelpful.
When Preston was a young boy, his grandmother used to lay out the dead. It was Preston's job to provide his grandmother with the necessary supplies for preparing the body, such as cloths, warm water, a dish of salt, and two coins for the ferryman. He was forbidden, however, from the actual work with the corpse, on account of his lacking a certificate in "doctrine." (Pills and potions and sawing off limbs and similar.)
Preston is a born healer, if not a doctor. A doctor requires letters put at the end of the name, and those letters are very expensive. The lack of formal training did not stop him from performing surgery on his mum's dog (made him right as rain when he pushed all the bits back in after being run over by a wagon) and on his granny's chickens (curing them of fowl crop, which even a talented pig witch can't do.)
Tiffany Aching finds him fascinating and intelligent, with a rare understanding of the world. Preston shares with Tiffany a delight in language and an imaginative take on vocabulary. He quietly and unobtrusively courts Tiffany, mainly by taking care of her when she is too busy to think of mundane things like sleeping and eating and being there for her when she needs it most.
After Preston assists in her defeating the evil which is walking the world, Tiffany wrests a promise out of Roland that he will sponsor Preston's further education at medical school in Ankh-Morpork. Preston became a medical student working at the Lady Sybil Free Hospital, studying under the excellent Doctor John Lawn. In the final book in the series, Dr. Lawn promoted Preston to surgeon (The Shepherd's Crown).
Tiffany is grateful to and admiring of Preston, even somewhat fond of him. She thinks of him as a "young man of considerable resourcefulness" until Preston points out that he's a year older than she is. By the end of I Shall Wear Midnight a mutual romantic interest between him and Tiffany is indicated. They reach an even warmer understanding in The Shepherd's Crown, leaving readers expecting them to share a promising future together.