I’ve seen a couple of the BBC television series, and I agree that they definitely found the right person to portray Cadfael in Derek Jacobi. Did they make a show out of every single book? I’ve always wondered that.
Thirteen of the twenty books have been adapted for the television, to wit
One Corpse Too Many
The Sanctuary Sparrow
The Leper of St Giles
Monk’s Hood
The Virgin in the Ice
The Devil’s Novice
A Morbid Taste for Bones
The Rose Rent
St Peter’s Fair
The Raven in the Foregate
The Holy Thief
The Potter’s Field
The Pilgrim of Hate
(Transmitted in that order. Last three went out in 1998, so who knows? they may finish the series yet.)