Partially based on true events that Sahni himself witnessed in the communal riots during Indias Partition in 1947, the novel follows the life of people from both communities - Hindu and Muslim, and from various classes and backgrounds, as tensions in cities build up. Like most Partition fiction, Tamas(meaning Darkness) too identifies the complex nature humanity and inhumanity that drives people to massacre each other. Eschewing grossly simplifying explanations for these murderous rages, the novel looks into the multiple simultaneous drives that lead people to kill others, and yet, save some others they were supposed to kill.
Rather than following a single persons fate during the riots, as Train to Pakistan did, Tamas takes a birds-eye view of the communal tensions raging through India, and how they were inextricably mingled with politics, economics and lies, not just on the part of the British who followed the policy of divide-and-rule, but also on the part of both communities. The motivations of murder were far more complex than simplistic narratives of religious clashes - the latter being stereotyped - not that religion wasnt involved - but that it was not the only thing of consequence involved.
It is difficult to write a review of a book like this. Partition is not something I can elatedly talk about, nor are the style/narrative/stylistic features a consideration in an issue like this.
Only, next time, Id rather read it in Hindi - the English translation is often clumsy, and not effective.