Heirs to Merlin: The Stonehenge Tribunal (Ars Magica Fantasy Roleplaying)
David Chart has been writing forArs Magicasince 1993, although this is the first book he's written all by himself.  He lives in Cambridge, which is why Cambridge rather than Oxford gets the magi, and has attended a roleplaying event at the School of Pythagoras (yes, it's a real place, not just a covenant).  When not gaming, he works on the history and philosophy of science, which gives him an excuse to doArs Magicaresearch as part of his real job.