Mutual Aid: A Factor of Evolution is book written by Peter Kropotkin on the subject of mutual aid while he was living in exile in England. The book was first published by William Heinemann in London in October 1902. Prior to that, the individual chapters were originally published as a series of essays in the Nineteenth Century between 1890 and 1896.
Written partly as a response to Social Darwinism and in particular to Thomas H. Huxley's own Nineteenth Century essay The Struggle for Existence, Kropotkin drew on his experiences in scientific expeditions during his time in Siberia to illustrate the phenomenon of cooperation in animal and human communities. After examining the evidence of cooperation among the animals, the "savages", the "barbarians", in the medieval city, and in modern times, he concludes that cooperation and mutual aid are as important in the evolution of the species as competition and mutual strife, if not more important.
http://www.calresco.org/texts/mutaid.htm