• Holly Roth, The Content Assignment (aka The Shocking Secret, 1954). When a female CIA agent disappears, a British journalist sets out to find her. Sadly, Roth died at age 48 after falling off a boat.
Upton Sinclair, ca. 1906. NYPL
• Upton Sinclair, World's End (1940). The first in a series with spy Lanny Budd by the author of The Jungle.
• Ross Thomas, The Cold-War Swap (1966). Thomas's Edgar-winning debut.
• Trevanian, The Eiger Sanction (1972; film 1975). The first in a series with assassin Jonathan Hemlock.
• Leon Uris, Topaz (1967, Hitchcock film 1969). A Soviet spymaster defects.All of the posts can be found here.