2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/29617The organizers of the Memorial Session for Herman Rietschel asked that I review some of the history of the interplay of superconductivity and spin fluctuations. Initially, Berk and Schrieffer showed how paramagnon spin fluctuations could suppress superconductivity in nearly-ferromagnetic materials. Following this, Rietschel and various co-workers wrote a number of papers in which they investigated the role of spin fluctuations in reducing the T_c of various electron-phonon superconductors. Paramagnon spin fluctuations are also believed to provide the p-wave pairing mechanism responsible for the superfluid phases of $^3He$. More recently, antiferromagnetic spin fluctuations have been proposed as the mechanism for d-wave pairing in the heavy-fermion superconductors and in some organic materials as well as possibly the high T_c cuprates. Here I will review some of this early history and discuss some of the things we have learned more recently from numerical simulations.9 pages, 10 encapsulated figures, Presented at MOS99, International Conference on Physics and Chemistry of Molecular and Oxide Superconductors, Stockholm, Sweden, 28 July-2 Aug, 1999, corrected typosStrongly Correlated ElectronsSuperconductivitytext