I love Len Deighton’s 10 book series featuring the character Bernard Samson and I have now read a few of the “Unnamed hero”/”Harry Palmer” books, although in no particular order. I just can’t get particularly excited about them. This one is the best so far and even so, I’d say it is a three-and-a-half star book. You get the impression that he is writing now with Michael Caine in mind. (The film of The IPCRESS File, starring Caine, was released the year before this book was published. Not a lot of people know that.)
Having said that, the dialogue sparkles and things proceed at a jaunty pace. Story-wise, though, things don’t really get going until “Harry” gets to New York, about half way through the book.
Overall, my advice to potential readers of Deighton’s work is to start with the Samson series. From there try SS-GB and XPD and then this series.