Alistair Maclean books are often divided into four phases in his life:

• 1955 (HMS Ulysses) - 1959 (The Last Frontier)
• 1960 (Ice Station Zebra) - 1965 (The Satan Bug)
• 1966 (When Eight Bells Toll) - 1971 (Bear Island)
• 1973 (The Way to Dusty Death) - 1986 (Santonrini)

It is interesting to note that the couple of books he wrote under the pseudonym Ian Stuart cam just after phase 1. The latter books (phase 4) are considered by some to be weaker - however they include several which were made into films and perhpas should be seen as a change in penmanship - a more relaxed 'ripping yarn' compared to the taughter earlier books.