  Expository notes on Clifford algebras and spinors with a detailed discussion
of Majorana, Weyl, and Dirac spinors. The paper is meant as a review of
background material, needed, in particular, in now fashionable theoretical
speculations on neutrino masses. It has a more mathematical flavour than the
over twenty-seven-year-old "Introduction to Majorana masses" by P.D. Mannheim
and includes historical notes and biographical data on past participants in the
story.
