The magazine paid Zola 20,000 francs for the serial rights. It appeared in book form immediately afterwards, published by Charpentier in March 1890, and very quickly sold 60,000 copies.

This was not the first time that Zola had written about murder. On 24 December 1866 Le Figaro had published his short story ‘Un Mariage d’amour’, a tale of adultery in which a husband who proves an obstacle to his wife’s amorous adventures is drowned by the two thwarted lovers in the Seine. A more substantial account of murder, again in the context of an adulterous love affair and again incorporating the drowning of the husband, occurs in the novel Thérèse Raquin, which had appeared in 1867. Thérèse Raquin does not belong to the Rougon-Macquart cycle, yet in the prominence it gives to sexually related violence and in the macabre, nightmarish quality of some of the episodes it contains it has as strong an affinity with La Bête humaine as any of the Rougon-Macquart novels. In his preface to the second edition of Thérèse Raquin in 1868, Zola refers to the bestial, soulless character of his two murderers. ’Thérèse and Laurent are human animals, nothing more ... the soul is entirely absent ... The murder they commit is the outcome of their adultery, an outcome that they accept as wolves accept the killing of a sheep.‘2 In the same year, writing as a journalist for La Tribune, Zola had also contributed an article on the trial in Marseille of three women accused of poisoning. ’It is good,‘ he says, referring to the trial, ’that human depravity is sometimes paraded before the public. Novelists are often accused of simply taking pleasure in such infamous acts. On the contrary, by making discussion of such crimes public they perform the same service as a court of law.’3 In the same article he makes the point that a novelist wishing to portray the bestial side of human nature could not have invented characters of a more instinctively criminal disposition.

At an early stage in his planning of the Rougon-Macquart cycle Zola had made provision for including a novel about crime and the law. The eminent critic and literary historian Hippolyte Taine (1828-93), whose opinion Zola had sought in connection with Thérèse Raquin, had urged him to reach beyond the closet world of private, domestic conflict and to write novels which, in the manner of Honoré de Balzac’s (1799- 1850) La Comédie humaine, would be a mirror of society. Taine’s advice undoubtedly prompted Zola to broaden the scope of his family history. The novels would still focus upon individual members of the Rougon-Macquart family and describe their personal fortunes, but they would also be directed outwards to demonstrate the social context in which these personal stories occurred. The series, when completed, would offer a panoramic view of Second Empire society as a whole.

Crime and the law being one of the many ‘inner’ worlds which went to form the larger, corporate world of the Second Empire, Zola had decided that it would be given a place of its own. Writing to his publisher, Lacroix, in 1868, Zola included in the list of ten novels that he initially envisaged as making up the series a novel set against the background of the law courts. Although at this stage Zola provided no details of plot, he had decided that the hero of the novel would be Étienne Lantier, whom he describes as ‘one of those born criminals who, although not mad, are suddenly driven by some animal instinct to commit murder’.4 The idea that murder is a product of some ‘animal instinct’ echoes Zola’s comments on Thérèse Raquin and the three women accused of poisoning in Marseille. But he now goes further; he sees Étienne Lantier’s propensity for crime as something which may also be explained by reference to heredity. Zola had situated Étienne Lantier on the illegitimate branch of the original Rougon-Macquart family tree, a fourth-generation descendant of the drunken smuggler Macquart and the neurotic and eventually insane Adélaïde Fouque. But by the time Zola came to write La Bête humaine some twenty years later, Étienne Lantier had been given a prominent role in another novel, Germinal (where he figures as the leader of a miners’ strike and does in fact commit murder) and was ear-marked for a role in the final novel in the series, Le Docteur Pascal. Zola needed a different protagonist for his novel about crime and he provided Étienne with an older brother, Jacques, a late addition to the Rougon-Macquart family tree, but one which ensured that his new hero would have the same degenerate forebears as his predecessor. Jacques Lantier, like his brother, would be a ‘born criminal’.

Zola’s thinking about crime during the period immediately preceding the writing of La Bête humaine was influenced by his reading of a number of recently published studies in criminology. The most notable of these was a work by the Italian anthropologist Cesare Lombroso (1835-1909), L‘Uomo delinquente (The Criminal Man). Originally written in 1876, it had been translated into French as L’Homme criminel in 1887. Zola had read it carefully. Lombroso argued that most criminals were ‘born criminals’, drawn to crime by an atavistic instinct and by pathological characteristics which were often discernible in their physical appearance. Basing his account on a study of the physical characteristics of convicted criminals, he identified various ‘abnormalities’ (pronounced lower jaw, oversized hands, low forehead) which he claimed indicated a biological regression to a primitive animal state and even a predisposition to certain types of crime. A year before the appearance of the French translation of L’Uomo delinquente, the French criminologist Gabriel Tarde (1843-1904) had published his La Criminalité comparée (Comparative Criminology). Tarde had read Lombroso’s work in the original Italian and sought to challenge the assumptions that he was making. Criminals, he argued, were not just ‘born’; nor could they be regarded as a purely biological throw-back to a primitive form of existence. Heredity and social environment also contributed to the making of the criminal. If the criminal displayed what might be termed ‘regressive’ patterns of behaviour, it was because the circumstances of birth and upbringing had upset the normal balance of inherited characteristics relating to the past history of the species.