MacLean was at his best in early books like this one. There's deception after deception, with both the reader and the protagonist being fooled, though the reader's more in the dark than the protagonist. Pierre Clavell is the narrator, apparently recently kicked out of his job as head of security at Britain's top-secret biological warfare lab and now a private-investigator. There's a security breach at the lab, and toxins are missing, including one that can wipe out all life on earth within a short time and for which there's no antidote. It's up to Clavell to find the toxins and save the world.
When it comes to writing about men driven to extremes, it's hard to top MacLean. Clavell is sliced and diced and beaten and choked and so on. He doesn't sleep in the course of the novel, which spans a couple of days. I don't recall that he eats, either. MacLean throws curve after curve into the story as the plot not only thickens but gets goofier and goofier. And, yes, I still loved every page of it.