The publishers of this series, "The Unexplained," indulge in some exaggeration when they say that the books "explain the science behind mysterious events and tell the stories behind unexplained occurrences." Most of the so-called evidence is anecdotal, unverifiable, and presented without documentation. Each book is divided into four chapters: explaining the mystery, relating some history of belief in it, describing investigations, and summing up the evidence (mostly non-existent). Precognition, telepathy, and clairvoyance are forms of ESP that have been reported around the world for centuries—many people believe they have had ESP experiences, like predicting later events or finding missing suspects. In the 1880s some scientists began to study the phenomenon. Research has involved subjects identifying unseen cards, describing hidden pictures or faraway places, and sending telepathic messages to sleeping people. The American government has tried similar experiments; though findings are inconclusive, research (now with the computer as a tool) has continued. The publishers state they are aiming to capture the attention of reluctant readers with the exoticism of the subject matter, a controlled vocabulary, short sentences, and an uncluttered format. While middle readers may be intrigued by these mysteries in spite of the uninspired writing, it is equally important that teachers and parents make sure students realize that a scientific investigation depends on verifiable proof and that a report on research must be fully documented to be taken seriously. It is fun to read about mysterious happenings, but in this series their origins remain unexplained.