A new class of materials based on a spirodilactam structure has been recently synthesized as part of research into new polymeric materials. Not only is the spirodilactam structure novel, but it was not even the intended product in the synthesis as originally designed. The polymerization process discovered by the reaction of 4-ketopimelic acid or its corresponding spirodilactone with primary amines opened a new field of polyspirodilactam chemistry. This paper describes the chemistry leading to the discovery of spirodilactam-based polymers and initial applications in the area of thermoplastics and thermosets. Most recent developments to be covered include aromatic spirodilactams and isomeric spirodilactams.