As the field of macromolecular science celebrated its 100th anniversary in 2020, we organised a special issue of Polymer International devoted to the synthesis, processing and applications of polyaryletherketones (PAEKs). Developed over 40 years ago, PAEK polymers and their composites experienced a steady increase in use and applications due to their unique characteristics: high mechanical performance, high toughness, high operating temperatures, low wear, non-flammable and chemically resistant as well as their function as a class of bioinert, robust biomaterials. The contributions to the special issue engage the materials science community and include a mixture of spotlights, perspectives, reviews, and research papers, spanning the breadth of basic science and engineering to applied technical/medical science, with authors from academic and industrial backgrounds, which reflects some of the exciting recent developments in PAEK-based materials that is of interest to a broad readership. A further area of research not particularly highlighted within this review; but very much an active concern; is the development of PAEK-based thermoplastic composites for application in the aerospace and medical sectors.