The Dark is Rising Radio Play
At the Weirdness adjacent blog Wyrd Britain, Ian Holloway posts about the 1997 Radio 4 adaptation of Susan Cooper's absolutely seminal fantasy novel.
Published 8 years after it's predecessor, 'The Dark is Rising', returned Susan Cooper to her Arthurian world but relocated the action from Cornwall to the Thames Valley.
The story of Will Stanton, last of 'The Old Ones', is another episodic quest as the newly minted magician comes into his power by locating lost artifacts. What elevates this beyond that first book however is Cooper's commitment to developing a coherent, mythic storyworld that is interwoven with icons of folkloric Britain, something she would continue to elaborate on across the rest of the series.
The Dark is Rising (radio play), Wyrd Britain
I've actually ONLY ever read The Dark is Rising out of the series but I've always thought it was a wonderful book.