PolyArylEtherKetones (PAEK) have been described as the world's highest performance true thermoplastic polymers. It is now 30 years since the invention of Victrex PEEK (PolyEtherEtherKetone) and PAEK are found in niche applications in almost every industry sector. PAEK are produced by several suppliers. As the market has grown an ever increasing range of products forms has been developed. These include higher temperature variants such as PEK, PEKEKK, PEEKK and PEKK and also compounds, blends, composites, films, shapes, coatings and medical grades. PAEK find applications in the automotive, chemical process, oil and gas, aerospace, medical device, telecommunications and electronics industries. They are often used because of a combination of properties which goes far beyond temperature resistance and includes resistance to wear, chemical environments, hydrolysis, sterilisation and fire together with biocompatibility, purity, low smoke and toxic gas emission and electrical performance. This review provides an overview of all the key aspects of PAEK technology including their production, characterisation, product forms (including compound, blends, composites, films, coatings and medical grades) and classes of application in each industry sector. It includes the many of the key historical developments and discusses up to date information on manufacturers, product forms and applications.