In "Dial M for Muriel" crime writer Val McDermid discusses Muriel Spark - crime novelist. Muriel Spark was a Scot, an exile, a poet, a codebreaker, a convert to a particularly Calvinist form of Catholicism from a particularly low-key Judaism and the cosmopolitan author of slender, sophisticated novels whose bestselling book mined her own schooldays in the Edinburgh of the 1930s. She may be most famous for "The Prime of Jean Brodie" but she wrote more than 20 novels, plus poems and plays. She is a writer of many facets, all of them glittering, and is now recognised as the most important Scottish writer of the 20th century. In this series, five Scottish women writers give five very different takes on the novels and life of Mrs Spark.