After publishing three books with George Smiley (GS) in a major or minor role, and one spy novel without him (A Small Town in Germany), John Le Carré (JLC) produced the monumental "Karla"- trilogy with GS as the undisputed hero.
This volume, first published in 1974, is Part One of the trilogy and in this reviewer's opinion JLC's very best creation among many other masterpieces. The principal theme in the book is the search for a "mole", an inside man turned traitor, within the higher echelons of the Circus, which runs some 600 agents worldwide. There have been inexplicable failures and disappointments. Control, the nameless head of the Circus is becoming suspicious of all of his staff, at a time when his health is declining rapidly. He becomes an increasingly marginalised person, poring over piles and piles of files, when a new source managed by a man keen to take Control's place, begins to enthral Whitehall with high quality reports...
Suddenly brought out of retirement, GS attends the debriefing of a rather dubious field agent and is requested to pursue the outcomes of the interview. In utter secrecy, GS starts his campaign to find the mole, aided by the trusted Peter Guillam and Retired Inspector (Special Branch) Mendel, who appeared first in JLC's debut Call for the Dead.
What makes this book exceptional is its plot, its dialogues, its atmosphere and more than ever, its characters. Chapter One about unhappy public schoolboy Bill "Jumbo" Roach meeting ex-betrayed spy, shot in the back, Jim "Rhino" Prideaux, ranks among the greatest first chapters in spy novels, on par with Trevanian's opening of The Loo Sanction. Totally brilliant.