Rumors of Nigeria’s demise have been somewhat exaggerated. This turbulent and magnetic African megastate endures despite its intense regional, religious and other divisions (the country has an estimated 250 ethnic groups and more than 500 languages).

Nigeria did fracture once, however, and it is this story that Chinua Achebe, a giant of African letters, tells. His memoir of the moment describes when the country, yoked together artificially by British colonizers, split apart at a cost of more than a million lives.

Nigeria is the Texas of Africa: it’s big and loud and brash, a place of huge potential, untapped talent, murderous conflict and petroleum riches. It also has a singular capacity for irony and self-reflection that is both cultural habit and survival tactic. It is difficult and often dangerous to get by in Nigeria unless you are a fortunate member of the infinitesimally small and mostly corrupt oil-fed elite. Acute awareness of your surroundings is a necessity; along with it goes another Nigerian trait, thinking and dreaming big.

All these characteristics were in play when the nightmare for weak nation-states became reality in 1967. Seven years after Nigerian independence, the prosperous Ibos, dominant in the eastern part of the country and targets of persecution and pogroms, declared their independence. Led by the charismatic Oxford-educated, Shakespeare-loving Col. Odumegwu Ojukwu, the fledgling nation called itself the Republic of Biafra. Achebe, an Ibo himself and the new country’s pre-­eminent intellectual, a product of Nigeria’s finest ­English-style schools and author of “Things Fall Apart” — soon went to work at Biafra’s Ministry of Information, serving as special envoy and chairman of a committee charged with writing a constitution for the new country.

The architects of Biafra were correct in their frustration with the Nigerian government, which did not intervene as thousands of Ibos were massacred. But they were deluding themselves that Biafra was viable. The nascent state had virtually no chance of survival once the authorities in Lagos decided they were going to stamp out the secession in what they called a “police action.” Was Biafra ever really a “country,” as Achebe would have it? It had ministries, oil wells, a ragtag army, an often-shifting capital, official cars (Achebe had one) and a famous airstrip. But as a “country,” it was stillborn.

Nonetheless, for over two brutal years, the Biafran war dragged on at the insistence of Ojukwu — described as “brooding, detached and sometimes imperious” in a 1969 New York Times profile by Lloyd Garrison — and meddling international players. Hundreds of thousands of civilians were killed. As many as 6,000 a day starved to death once the federal government blockaded the ever diminishing Republic of Biafra. But Ojukwu refused to give up. The final death toll was estimated at between one and three million people.