“Buddha” is one of the Penguin Lives Series of biographies of famous people. Amazon.com has very many entries for Karen Armstrong. (For her books I've read, click on her name.)

This book is about Buddha and Buddhism as it existed then. A major difficulty is that Buddhist scripture doesn’t have the equivalent of Jesus’ Synoptic Gospels that give us a semi-historical account of Jesus’ life. Finding semi-historical facts about Buddha the man is difficult, but the main threads exist. Siddhatta Gotama renounced his life of secluded privilege when he learned of suffering, death and the real world outside his palace. He gave up everything to become a monk. He began with yoga and became a yogin (a master of yoga), then realized that neither asceticism nor yoga gave him the enlightenment he sought. He realized that the idea of an eternal Self (or Soul) was another delusion of the (then traditional) Vedic religion. There is no eternal, unchanging Self – the self is not static but always changing – the self is a process, not a stasis.

He learned that a complete lack of selfishness is essential to experience true compassion. His Four Noble Truths are 1) suffering infuses human life; 2) desire causes suffering; 3) Nirvana is a way out; 4) his Eightfold Path can give Nirvana (or total enlightenment). Nirvana is “Nothingness” only in the sense that no words can describe it, although some attempts have been: the Truth, Peace, Purity, Safety, Freedom, the Everlasting, the Other Shore, the Refuge, the Beyond, and the Ultimate Goal. But only monks can achieve Nirvana; a layman can only improve his next reincarnated life. Gotama only reluctantly accepted nuns into his order, but with a status below that of monks. He gave up his Nirvana for 45 years to teach others what he learned. Only at his death did he let himself achieve his state of Nirvana – an utterly safe Refuge and an incomprehensible Peace that is in many ways reminiscent of words that monotheists have used to describe God, or being in Heaven and with God. Karen Armstrong writes a well-researched book but this one is perhaps a bit too concise for the topic.