The books he wrote follow familiar patterns: a flawed but ultimately decent protagonist works within a rotten bureaucracy and feels disillusioned. He encounters something or someone that could break the dreary mold and force happy improvement in the system whilst affording some personal redemption. Yet apparatchiks behind-the-scenes have cottoned on all along, and foil the plan with a casual cruelty born of long experience. At best, the protagonist gains a Pyrrhic victory fraught with loss and pain. At worst he dies, or his good intentions are warped - as with literal or figurative torture - before his fatigue-stressed eyes. A romantic interest usually acts as collateral damage, and as an example of feminine virtue. On occasion at the end the whole shebang is flipped on its head: what the protagonist has done sets off something even worse, perhaps unleashing his own latent ruthlessness.
It's a sturdy mannequin for a story, and it bore dressing up in many different outfits and contexts as the decades slipped by. John le Carré moved between the espionage mainstay of Russia versus the West, through deeply personal and semi-autobiographical character studies, to the chaos following the collapse of the USSR, to the thick belt of sleaze ringing modern ultra-capitalist misdeeds: the arms dealers, pharmaceutical giants, warmongers, gangsters, plunderers, ideologue bigots, flag-shaggers.
Yet to say he simply retold a story with deftness many times is unfair. His books, particularly from the 1980s on, were meticulously researched with travels and meetings with pertinent people draped in murk. Owing to his position as ex-spook, le Carré became one of precious few writers to utilise their reputation into yet more solid output. There is immense range in le Carré's writing, room aplenty for divergences and surprises; it takes a good novelist to hone a form to near-perfection, and a great one to then adroitly subvert and morph it. He also had a fine strength in eliciting sympathy for all sorts of creeps, washouts and bad guys, laying out revolting motives we grudgingly understand. His best novels leave readers shattered and disillusioned, but cannier and enlightened: seldom are humanity's symphonic ugliness and virtues done so raw, laid so bare.
For this reason I heartily recommend le Carré's books to the board, as entertaining tonic and mental grounding through this isolated, plague-swathed winter. His books contain character treatments that resound in the NPA theory, and it's a joy to see some personality crop up and behave accordingly. Acquaint yourself with The Spy Who Came In from the Cold, progress to the Karla trilogy: Tinker, Tailor, Soldier, Spy; The Honourable Schoolboy; Smiley’s People, before moving on to the post-1991 stuff. The two TV series depicting Smiley are brilliantly acted, as in this scene with Alec Guinness's Smiley interrogating Bernard Hepton as Toby Esterhase: