Ray’s antipathy towards having Feluda drawn into contemporary political and social settings has a deeper root: he didn’t like what he saw happening around him. This bhadrolok abhorred the breakdown of reason, the flood of chaos, unthinking violence and unintelligent criminal acts – even if he had separate problems with middle-class hypocrisy and behaviour.

But there was an ambiguity, as is evident in Ray’s Calcutta Trilogy – the films Pratidwandi (The Adversary, 1970), Seemabaddha (Company Limited, 1971) and Jana Aranya (The Middleman, 1975) – and in his late film, Ganashatru (Enemy of the People, 1989), where Ray does let the political and social muck in.

At the time of writing Gangtoke Gondogol and Sonar Kella in 1970–71, he wrote to his biographer and friend Marie Seton describing Calcutta as a “nightmare city” and toying with the idea of leaving it. There was a compelling reason why Ray found the chaos outside the world of films and books distasteful: it was personal.

As he told Andrew Robinson (in Satyajit Ray: The Inner Eye), “I might have understood more the young peoples’ minds if my son had taken to that movement. But he was a victim. Sandip was surrounded and threatened with a dagger when he turned up for his BA exams. They told him, ‘You are the son of Satyajit Ray. We’ll see how you can pass this examination.’” But there was another reason for Ray’s desire to remain an “apolitical” film-maker and writer. He found getting artistically involved unaesthetic.

Which brings us to the nub of the matter: Feluda was the crystallisation of Ray’s unease with Bengali middle-class straitjacketing and delusional self-imaging, as well as with his natural distaste for the populist, the garish, that somewhere in his mind, slid down to the all-too-visible lumpen. Felu Mittir holds the key to maintaining an equal distance from the ossified bhadrolok (cultured man) and the rampaging chhotolok (lumpen).

Ray’s bilingual genius applies not only to his mastery over the languages of Bengali and English, or over his equally vast and deep knowledge in matters Indian and “Western”, but also to his ease with Bengali high and popular culture. Consistently, in his Feluda books, Ray simultaneously tapped and displayed his closeness and fondness for the demotic, his natural affinity towards middle-class colloquialisms.

The early, younger Feluda is particularly comfortable playing the foil, rather than adversary, to (Narayan) Debnath’s Bantul the Great or other pop-cultural icons in the Bengali universe. We hear him snap playfully at Topshe with a “Pakami korishne” (Don’t act smart). He is equally at ease displaying his irritation with lazy reasoning as he is with bad taste. Such as when we meet him in the opening pages of Gorosthane Sabdhan, berating Lalmohan “Jatayu” Ganguly for the second-hand Mark 2 Ambassador he has bought.

“Until you change that grotesque horn of yours and get a civilised one instead, that car is forbidden to enter Rajani Sen Road [where Feluda and Topshe live with Topshe’s parents].”

Jatayu looked apologetic.

“I knew I was taking a big risk,” he said, “but you know the salesman was demonstrating – somehow I couldn’t resist the temptation. It’s Japanese, you know.”

“It’s ear-splitting and nerve-wracking,” said Feluda. “I could never have believed that Hindi films would influence you so soon. And that colour – equally unbearable. Just like what you see in Madras films.”

In the 1979 novel, Chhinnamastar Abhishap, a quieter, more ironic Felu again takes on Lalmohan, the title of whose new thriller, Vancouverer Vampire – in keeping with his proto-Karan Johar alliterative titles – he finds deeply problematic.

Topshe narrates, “He had said that Vancouver is a very modern city, and for vampires to stay there is impossible. To which Lalmohan-babu replied that after he had scoured through Horniman’s geography book, he figured that would be the best title.”

These make for comic situations before the actual adventure begins, or in between situations that call for seriousness. But at some fundamental level, Jatayu is the representative of the Bengali middle-class middle-aged man whom Ray wants to befriend and educate at the same time through Feluda. It would not be an exaggeration to say that Feluda’s raison d’être is as much to try and inculcate the likes of Lalmohan Ganguly with the right kind of reasoning (and, by some miracle, the right kind of taste) as it is to solve mysteries.

Which brings us back to the binary Bengali universe of the bhadrolok and chhotolok. The figure of the bhadrolok is quite well established even outside the immediate domain of Bengali cultural politics.

In terms of class, the bhadralok (the female equivalent is bhadromohila, but doesn’t quite transfer the same qualities) can range from the archetypal rich, upper-middle-class Bengali gentleman to the middle-class Bengali gentleman whose relative lack of wealth is compensated for by his ability to stand out with dignity in a crowd. Amartya Sen is a bhadrolok. Jyoti Basu, Buddhadeb Bhattacharjee and much of the old guard of the Bengali Left leadership are considered bhadrolok. Lalmohan Ganguly, by dint of his affable nature and jolly spirit, just about makes it into the fold. Satyajit Ray himself was a bhadrolok, however critical of his own tribe he may have been.

The chhotolok (literally “small man”) is a more tricky archetype to bottle. At its most basic, the chhotolok is crass, uncultured, a specimen to be equally feared and be repelled by. Usually he shows signs of drunkenness and lewd behaviour, uses foul language and is terribly devoid of capital C-ed Culture. He would be the one who, if getting his hands on some money, will go out and buy a garish green car with a loud horn. And above everything, he is loud – and is sated by what Feluda disparagingly calls “Hindi films”.

In the world of criminals and imposters that both Feluda’s stories and the world we live in share, the chhotolok has sinister, antisocial overtones. In Feluda’s moral universe, he is the vicious villain.

Take the two villainous kidnappers in Sonar Kella: Bhabananda aka Amiyanath Barman, alias the Great Barman – Wizard of the East, who pretends to be the parapsychologist Dr Hemanga Hajra, and his partner in crime Mandar Bose. While Barman, the leader of the duo, comes across as the criminal mastermind that he is – “This man seemed too shrewd. Besides, he was much too tall and formidable-looking. Not at all what we think of when we say, ‘Dr’” – Mandar Bose is a cut-throat and fits the bill. The talentless ruffian is Ray’s chhotolok.

The most obvious “chhotolok” in the Feluda pantheon of villains, however, is Maganlal Meghraj. Ray via Topshe describes him: “The eyes that regarded us solemnly were sunk in, set under thick, bushy eyebrows. A blunt nose, thick lips and a pointed chin completed the picture. He too was wearing a kurta-pyjama. The buttons on his kurta might well have been diamonds. Besides these, on eight of his ten fingers flashed other stones of every possible colour.”

Ray’s disdain for flashiness – what in present parlance would be “bling” – immediately sets the oily Maganlal up as a chhotolok villain. To drive the point further home, Ray has the Benarasi Sethji throw Feluda a wad of currency notes as a bribe to stop meddling in the case. “There is three thousand here, Mr Mittir. Take it. Take it and relax, enjoy yourself with your cousin and uncle.”

In Satyajit Ray: Portrait of a Director, Marie Seton points to Ray’s very Bengali middle-class bhadrolok attitude towards money. “Wealth, which once was little respected in comparison to wisdom, now wields more power over the imagination than it ever did before in India. Satyajit, who counted the pennies throughout his youth, seems to have equated wealth with impecuniosity of spirit, if not active evil, in all his films.” The same holds in Ray’s depiction of villains in Feluda stories, where the prime motive for villainy is almost always to possess unlawfully what is not that person’s property or object of value.

In a note to a Feluda collection, Ray had written in 1988, “To write a whodunit while keeping in mind a young readership is not an easy task, because the stories have to be kept ‘clean’. No illicit love, no crime of passion, and only a modicum of violence. I hope adult readers will bear this in mind when reading these stories.”

Reading this in conjunction with the knowledge that Ray refused to visit brothels for background research in his 1970 film Pratidwandi, it seems that Ray found writing “clean” detective stories for kids a relief. It was also where the usual traits of the chhotolok that he couldn’t bear could be conflated in the vice of greed and terrible taste. And it was Feluda who would strike the right balance between the bhadrolok in his bubble and the chhotolok in his den.

Excerpted with permission from Feluda @ 50, curated and edited by Boria Majumdar, HarperCollins India.