Call for the Dead (George Smiley #1) by John le Carré

John le Carré classic novels deftly navigate readers through the intricate shadow worlds of international espionage with unsurpassed skill and knowledge, and have earned him -- and his hero, British Secret Service Agent George Smiley, who is introduced in this, his first novel -- unprecedented worldwide acclaim.

George Smiley had liked Samuel Fennan, and now Fennan was dead from an apparent suicide. But why? Fennan, a Foreign Office man, had been under investigation for alleged Communist Party activities, but Smiley had made it clear that the investigation -- little more than a routine security check -- was over and that the file on Fennan could be closed. The very next day, Fennan was found dead with a note by his body saying his career was finished and he couldn't go on. Smiley was puzzled...

Novels by John le Carré in which the character George Smiley appears - with the exception of The Karla Trilogy, these are standalone works and can be read in any order. (In four out of nine of them, Smiley is only a minor character.)