In 14 chapters, these volumes cover broad concepts from "Afterlife Mysteries" to "Invaders from Outer Space." Each chapter begins with an overview and an outline of the topics and subtopics that are covered. Within the chapters, entries are generally arranged in alphabetical order. Each ends with a further reading list called "Delving Deeper." Glossaries are appended to each chapter and cumulated in volume 3. Occasional cross-references appear in bold type within the text to refer the reader to other entries, but since the set does not have a strict A-Z arrangement, one must use the index to determine where those entries are located. Because of the set's topical arrangement, the index is essential.