The book documented the near-death experiences (NDEs) of 26 children and became a New York Times bestseller.

[4] Morse had previously theorized that near-death experiences came from drugs administered during attempts to save someone's life.

Susan J. Blackmore in her chapter 'Near-death experiences' in The Skeptic Encyclopedia of Pseudoscience[7] discusses various alternative explanations for these experiences, including expectation, administered drugs, endorphins, anoxia (oxygen depletion) or hypercarbia (excess carbon dioxide) and temporal lobe stimulation.

Hypercarbia has long been known to induce strange effects such as seeing lights, visions, disconnection from the body and apparently mystical experiences.

[8] Blackmore concludes that temporal lobe stimulation due to anoxia and changes in the limbic system may also account for much of the classical near-death-experience.