The Arthur Case Wu series by Ross Thomas consists of 3 books, published between 1978 and 1992. The series begins with Chinaman's Chance.
The Mac McCorkle series by Ross Thomas consists of 4 books, published between 1966 and 1990. The series begins with The Cold War Swap.
The Philip St. Ives series by Ross Thomas consists of 5 books, published between 1969 and 1976. The series begins with The Brass Go-Between.