This is the first supplement to the encyclopaedia that was named an ALA Outstanding Reference Book. This work maintains the arrangement of the primary volume and is up to date late into 1998. It includes over a dozen new dinosaur genera and even more new species and new life restorations. Section One provides introductory text on subtopics such as "The Mesozoic Era", "Ectothermy Versus Endothermy", and "Dinosaur Extinctions". Section Two continues the workable ordering of dinosaur systematics. Section Three continues the alphabetical compilation of new dinosaur genera, and the last section continues the detailing of doubtful genera that have appeared in the palaeontological literature.