Things Fall Apart is a short novel by the Nigerian writer Chinua Achebe. It is one of the most famous novels from Africa (it's on numerous 'Top 100 Best novels' list; Time for example, or The Telegraph) and was first published in 1958.
It begins with an epigraph from W. B. Yeats' The Second Coming:
Turning and turning in the widening gyre
The falcon cannot hear the falconer;
Things fall apart; the centre cannot hold;
Mere anarchy is loosed upon the world.
This very much sets the tone for the book. It tells the story of Okonkwo, a warrior in the Igbo community of Umuofia in Nigeria. His father was a failure: a coward who left behind him nothing but debts, and Okonkwo vows not to grow into the same man: he is successful, hardworking, and a very powerful figure in the community, and he strives to be the archetypal 'man' which in fact makes him very controlling, domineering, unpredictable, and violent towards his wives. Any affection he feels, like that towards Ikemefuna, a boy given to the village by a neighbouring tribe as a peace-offering (along with a virgin), is well-hidden and when the village elder, Ogbuefi Ezeuder, tells him Ikemefuna must be sacrificed as retribution for the murder of a woman by the neighbouring tribe, Okonkwo insists on killing the boy himself, despite being warned against it. From here, things fall apart...
It's a very harsh novel on contrasts. We see the divisions between what is perceived to be 'true' masculinity and femininity, a man determined to be the opposite of his father, and we see a society in the process of change. One of the central themes is colonialism: after Okonkwo returns to Umuofia having been exiled for seven years Christian missionaries come to the village to convert them, telling them their gods are false, and the village finds itself torn between tradition and the change Christianity brings. Achebe describes the complexities of the tribe's life: the rules, the laws, the religion, and their day to day life, a contrast in fact to how tribal life is portrayed in the west. The clash, unsurprisingly, was bitter and violent. For this it is an excellent novel, but it may be extremely brutal to the western reader. I hope that wouldn't people off, though: it's a unique and valuable insight into precolonial Nigeria.