Frans Hals was born in Antwerp in around 1582, moved to Haarlem when he was three, found fame rather late, in his mid-thirties, died in 1666 – and was forgotten, at least outside his native country. The apparent lack of finish in his work made it unfashionable in the eyes of connoisseurs and collectors until interest in his paintings grew again in the mid-19th century. In 1865 Hals’s Laughing Cavalier was bought for a vast sum by Lord Hertford and exhibited in London to huge acclaim. Soon afterwards it entered the Wallace Collection.

The funny thing about the Laughing Cavalier is that the cavalier isn’t laughing at all. He has a merry eye but is surely smiling, not laughing, beneath those famous whiskers. And that was just as it should be in 17th-century Haarlem, at least if you were of some social standing. Hals loved to show his sitters in good humour. Along with the legendary brushwork, this is the most distinguishing feature of his work. But heaven forfend that his sitters should actually laugh. Remember the advice of the 18th-century Lord Chesterfield to his son: ‘I would heartily wish, that you may often be seen to smile, but never heard to laugh while you live. Frequent and loud laughter is the characteristic of folly and ill-manners; it is the manner in which the mob express their silly joy at silly things; and they call it being merry. In my mind, there is nothing so illiberal, and so ill-bred, as audible laughter.’

There was a crucial distinction between smiling and laughing and it had long been entrenched in European societies. We seem to have forgotten it, but it is one of the secrets to interpreting Hals’s art, where posh people smile and the lower classes laugh – indeed, in Hals’s pictures, they are often laughing their heads off. Hals never blurred the distinction. Steven Nadler rightly observes that ‘Hals’s oeuvre … may contain more laughs and smiles than that of any other painter in history’, but in this otherwise painstaking book there is no awareness of the difference between the two things (although in fairness, I am not sure anyone else thinks about it these days either). It was something that everyone at the time was acutely aware of. In Judith Leyster’s Self-Portrait of 1630, for example, the artist turns towards us with a smile on her lips, while on her easel is a painting of a fiddler laughing fit to bust.

Hals must, though, be alone in so determinedly seeking out good humour in his smart sitters. In the early portrait of the infant Catharina Hooft and her nurse (1619–20), the child smiles directly out at us, and Van Campen Family (1620s) is a study in carefully calculated degrees of smiling. Even an admiral, Pieter van den Broecke, is pictured smiling, ruffle-haired and looking right at us in as cheerful a portrait (c 1633) as you could imagine. And even less obviously friendly sitters are painted with warm sympathy: Samuel Ampzing, in an out-and-out masterpiece of 1630, is about to smile, we are convinced, while Maritge Claesz Vooght (portrayed in 1639) could clearly smile if only she would let herself do so. True, Hals had to paint some boot-faced types and he did not spare them, as in the case of the notorious paintings of the regents and regentesses of the Old Men’s Almshouse of Haarlem (c 1664). These two group portraits could hardly look more grim, so much so that they have been interpreted as revenge on the part of Hals for some mistreatment. That, Nadler explains, is nonsense: rejecting any satirical intent on the part of the artist, he suggests that they are simply Hals’s portrayals of serious people doing serious things. I don’t quite buy that, not with Hals. In each composition there is a messenger entering in the background, wearing a far more sympathetic facial expression than the main sitters. And, despite what Nadler says, one of the regents is definitely pissed, his hat tipping off his head, his hair falling over one of his glazed eyes.

Hals would never have made a mistake about that because he was quite brilliant at showing his sitters caught in the middle of an action, or even speaking, as in the portrait of Isaac Abrahamsz Massa (1626), who is seen twisted back in his chair, distracted from looking through a window and turning to address whoever has interrupted him, his lips parted, his eyes alert and focused on a point outside the canvas. In a marvellous work (c 1638), Willem van Heythuysen is shown tilting back in his chair (two of its four legs are in midair), something we all do but might not want captured in a portrait. But although Hals preferred his sitters to be amiable, he could also capture melancholy with acute sensitivity, as in his portrait of François Wouters (1645), whose eyes seem ready to weep, his mouth to cry.

And so what of the many Hals paintings that show people really laughing? For one thing, these are not portraits as such but genre pieces, and often examples of that very Dutch thing, a tronie, a study of an exaggerated facial expression. All these vigorous images were intended to evoke an emotion, tavern life or characters taken from the stage or folklore. But then there is the question, not addressed in this book, of why people bought such pictures. It wasn’t as if the lower classes themselves were filling the walls of their hovels with expensive canvases. The purchase of such paintings, which were not usually produced on commission but for the thriving open market, was confined to the comfortably off. In view of the strict rules of behaviour that were imposed by the Calvinist authorities – as this book reveals, every aspect of one’s personal life was scrutinised – perhaps these jolly pictures simply offered some much-needed light relief. Or maybe there was a less appealing element of self-satisfaction involved, as with the Pharisee in the New Testament, who thanks God that he is not like other men.

This raises another important question about Hals, which Nadler worries about throughout the book. Was Hals a Roman Catholic or a Calvinist? He was born in Antwerp and so was Flemish by birth and likely to have been baptised a Catholic. Hals’s father had certainly married his first wife (Hals was the son of his second wife) in a Roman Catholic church, and all the children of that marriage were baptised there. The question is significant in the context of the family’s move to Haarlem in Holland when Hals was just three, and for the whole matter of Hals’s patronage. As Nadler points out, Hals did not formally enrol as a Calvinist until well into his seventies, when joining the Dutch Reformed Church would have offered all sorts of social welfare benefits, something he sorely needed after a lifetime of money troubles. Nadler rightly emphasises how important Hals’s Antwerp background remained. His handling of paint is far more Flemish than Dutch – fluid, with little impasto – and in his early thirties he made sure to revisit his native city, bulging as it was with wonderful works by Rubens, as well as by Titian, among other examples of superb brushwork that Rubens had assembled. That three-month stay in 1616 was to determine the course of Hals’s career. When he returned to Haarlem, he easily established himself as a master for the first time.

Nadler laments the absence of biographical material about Hals, but does a wonderful job of bringing the social context of his art to life in intricate and lively detail. In so doing, he brings this incomparable artist to life as well. But let’s not forget that the Wallace Collection is going to need a new title for its most famous picture. May I suggest ‘The Politely Smiling Cavalier’?