I've been told that it does not matter in what order these books are read. They are all stand-alone stories and so I took a risk and skipped number 2 (I don't have a copy of that one) and went right to number 3. It seems fine to do so. Even book number one didn't seem like the first in a series.In this one, CIA operative Sam Durell parachutes into Russia to help prevent a rogue member of the Politburo, known as "Comrade Z", from launching one of Russia's first ICBMs toward the US. Sam Durell has a mere handful of days to stop this event which will happen on May Day. The book was first published in 1958 and it is interesting to see the perspectives between the US and Russia at that time. Also of interest is the similarities to Ian Fleming's Bond books which first began appearing in 1952.This novel was much as I expected. Lots of spy action without much spy craft. There is the usual good guys and bad guys and the occasional misconstrued identity. And, of course, there is the obligatory Bond, er Durell girl. The mystery part surrounds the identity of just who is Comrade Z. There is a nice climax at the end to wrap up the story.I enjoyed the first two Sam Durell books I've read so will keep on with them. They are quick reads so serve well as a break between weightier material.