Besso was born in Riesbach from a family of Italian Jewish (Sephardi) descent. He was a close friend of Albert Einstein during his years at the Federal Polytechnic Institute in Zurich, today the ETH Zurich, and then at the patent office in Bern, where Einstein helped him to get a job. Besso is credited with introducing Einstein to the works of Ernst Mach, the sceptical critic of physics who influenced Einstein's approach to the discipline. Einstein called Besso "the best sounding board in Europe" for scientific ideas. In Einstein's original paper on Special Relativity, he ended the paper stating, "In conclusion I wish to say that in working at the problem here dealt with I have had the loyal assistance of my friend and colleague M. Besso, and that I am indebted to him for several valuable suggestions."
Besso died in Geneva, aged 81. In a letter of condolence to the Besso family, Albert Einstein wrote "Now he has departed from this strange world a little ahead of me. That means nothing. People like us, who believe in physics, know that the distinction between past, present and future is only a stubbornly persistent illusion." Einstein died one month and 3 days after his friend, on 18 April 1955.
- Einstein and Besso: From Zürich to Milano by Christian BRACCO
- Einstein as a Student
- An Einstein Encyclopedia, Alice Calaprice, Daniel Kennefick, Robert Schulmann, p.65, Princeton University Press, 2015
- Einstein the Early years
- Calaprice, Alice; Lipscombe, Trevor (2005). Albert Einstein: A Biography. Greenwood Publishing Group. p. 24.