The motivation for writing this mini review is that many approaches to predator-prey (PP) systems have been discovered, overlooked, and then rediscovered again years later. Briefly describing some of the papers that physicists have written about the subject over the last 20 years thus seems advisable. This review contains no detailed formulas, model descriptions, or techniques; rather, it presents the authors? assumptions, main results, and conclusions. Some unclear points still exist, despite the time elapsed from the first papers, so this review might inspire you to open research in new directions.