They Never Looked Inside (US title - He Didn't Mind Danger) was Michael Gilbert's second novel, and it was originally published in 1948. It represents a major departure from the setting and style of his debut, Close Quarters, even though it again features Inspector Hazlerigg, who thus became the first of Gilbert's long list of series detectives. Whereas the first novel was a whodunit in the classic style, the second is an action thriller about a criminal gang.
The contrast between the two books is explained by the fact that Gilbert started work on the first before war broke out, although it was only published in peacetime. The second bears witness - as do many of its successors, such as Death in Captivity and Death Has Deep Roots - to Gilbert's wartime experience. The plot and many of the characters are derived from the experience of the Second World War, and despite Hazlerigg's presence in the story, the most intriguing character is the recently demobbed Major Angus McCann, who acts as an amateur sleuth, and whose intrepid nature gave the book its American title. (To explain the curious British title would require a plot spoiler, I'm afraid.)
The book opens with a robbery that goes wrong, and it soon emerges that this is one in a long sequence of crimes with which Scotland Yard is grappling unsuccessfully. McCann becomes involved in trying to figure out what is going on, and his bravery and pig-headedness are characteristics which are evident in a good many of the protagonists of Gilbert's later books.
Returning to this book for the first time since I was a teenager, I felt that it was interesting in itself, but mostly as a portrayal of its time (and be warned, this includes some racism on the part of some of the ex-soldiers in particular) and as a prototype for many of Gilbert's later books. In its day, it was very well reviewed, but really it's an apprentice work, and I have to say that the revelation of the criminal mastermind's identity (such as it is) comes as an anti-climax. Gilbert quickly became a highly accomplished storyteller, and if you haven't read him before, I'd recommend that you start with one of the books he wrote after this one.