The book is a collection of twenty-two articles (two of them book reviews) on various curiosities and wonders exploring the boundaries between science and pseudo-science.[1][4] "The[ir] common thread is [their] skeptical takes on subjects that are often muddled by paranormal and pseudoscientific claims."[5] De Camp viewed such phenomena from a skeptically rational viewpoint, pointing out the fallacies in supernatural and otherwise fantastic explanations. His debunking efforts were an important and characteristic feature of his nonfiction, and the present collection is a notable instance of it.[6]