Where the 1997 handbook contains 28 chapters, the new handbook contains 85 chapters divided over three volumes. Although the topics of the chapters all have obvious connections to item response theory, the tools are so general that these chapters felt more like chapters from a general statistics book. In addition, the book is very well edited, reflected by the comprehensively aligned notation across the different chapters and the thorough cross-referencing to chapters within this volume and chapters from the other two volumes.