Angus MacVicar (1908-2001) was a Scottish author of crime thrillers, juvenile science fiction and nonfiction. His first novel The Purple Rock was a bestseller, but his career was interrupted by an illness and then service in World War II with the Royal Scots Fusiliers.
He also later turned his hand to screenwriting, and his young-adult sci-fi novel series The Lost Planet was made into televsion and radio versions. (A side note: MacVicar's father was a Presbyterian minister in the Church of Scotland and the author's books often had snippets of Christianity in them, so it's interesting that The Lost Planet was the first science fiction series ever translated to Hebrew, and allegedly had considerable impact on the development of that genre in Israel.)
MacVicar's suspense novel The Singing Spider from 1938 was set against the backdrop of Mussolini and impending war with Italy. It follows young Archie Campbell, an intelligent, scrupulously honest and brave young man who is offered a job as a secret agent by Sir Robert Vanburgh, who is the Secretary for Diplomatic Affairs and also a friend of Archie's dead father. Archie's job is to visit the quiet little fishing port of Bennachie in order to uncover the secret that was discovered by another murdered agent, known as D7—who was also Sir Robert's son.
Archie takes the job hoping to find redemption following a scandalous love affair that left him a broken man and a drunkard, and soon finds himself immersed in the picturesque village of Bennachie playing the not-too-far-off role of a recovering invalid. Archie tries to uncover the identity of the Singing Spider—an Italian spy and master of disguise thought to be behind D7's murder—with the help of an American Professor, a local rogue who's also seeking redemption, and a lovely young minister's daughter. But first Archie has to find out how the Singing Spider is tied to a puzzling phrase that translates as "The Pit of Baal" and the mysterious red lights at the Bennachie stone, an artifact the Professor believes dates back to the ancient Phoenicians.
It's definitely a novel of its time, thematically and stylistically, but there's a good rendering of the Scottish setting that was so similiar to areas MacVicar knew well, and to its characters. There's also a bit of naive sweetness to it that you don't often find in spy-themed suspense novels, no doubt a nod to the author's Presbyterian roots and his young-adult writings. It's definitely a G- or PG+ type of plot. The Singing Spider was made into a radio program for BBC Scotland in 1950, although I doubt any traces of it exist. As a matter of fact, there is very little about the author of this book on the Web, and unless you can find his works at your local library, you may find it difficult to get your hands on them.