I present a very personal account of the way in which, in the approximately 12 months between July 1972 and July 1973, we came to a theoretical understanding of the puzzling experimental data on what we now know as superfluid 3-He. I particularly emphasize the concept of “spontaneously broken spin-orbit symmetry” which turned out to be a key
ingredient in understanding the NMR behavior.

(The Nobel lecture as given in Stockholm, slightly expanded.)