OMG I'm glad there are other John D. MacDonald fans of his Travis McGee mystery/action series!
There are 21 novels in the series, each named after a color: The Deep Blue Goodbye
, Nightmare in Pink
, A Purple Place for Dying
, ... -- the first three in the series, the whole series published between 1964 and 1985. I've realized there are probably more MacDonald novels not in the McGee series that I haven't read--and looking forward to researching which they are and reading them. (MacDonald died in '86 not long after his last McGee novel was published.)