Juan José Benitez, born on December 14, 1946, in Pamplona, Spain, is a journalist, writer, and researcher. With a career spanning over four decades, he has written numerous books on various topics, including UFOs, paranormal phenomena, and mysterious events. Benitez's work is characterized by his meticulous research, in-depth analysis, and engaging writing style.

However, some readers may find the book's dense and detailed content overwhelming, and the author's conclusions may be considered speculative or even controversial by some. Additionally, while Benitez presents a compelling case for government cover-ups, the lack of concrete evidence and reliance on anecdotal testimony may leave some readers skeptical.

The "Materia Reservada" series, which translates to "Reserved Matter" or "Classified Matter," is a collection of books that delve into the unexplained and the unknown. The series has become a benchmark for investigative journalism and has garnered a massive following worldwide. The books are characterized by Benítez's meticulous research, in-depth interviews, and a critical analysis of the evidence.