Richardson's style reminded me quite a bit of the Ludlum novels I read as a teenager. It's a quick read with intricate twists and turns, but as with Ludlum's works, the conspiracies and intrigue are nothing without great characters. Ultimately it's those characters and the way their backgrounds bubble up to explain their motivations that really made this story work. Sure there's a great deal of spy vs. spy action as well, but the character details are the glue that holds everything together.
The other aspect of her style I absolutely loved is that this is set in 1980. There are no computers, no cellular phones, no James Bond Q-Branch gadgetry... Elliot and the rest of the gang have to rely on tried and true spy methods. Codebook stuffed in a hollowed-out heel of a shoe? Check. Microdot copy of a map to Nazi treasure? Check. Standard hand-to-hand, knives, and guns? Check. And in most cases, Elliot is forced to use is brains to think his way out of problems more often than not.
As I read along, I couldn't help but think the book would make a great movie in the style of the James Bond films of the 1960s and 1970s. I'm not sure who they'd get to play Elliot, but perhaps someone like Tommy Lee Jones could pull it off.
The Thyssen Affair was a fast, enjoyable read. If you're looking for a good spy novel from the Cold War, be sure to check it out.