Paranormal Investigations: Aliens, UFOs, and Unexplained Encounters
World History: The Mysterious Maya Civilization
Viewpoints on Modern World History: AIDS and Other Killer Viruses and Pandemics
Paranormal Investigations: The Bermuda Triangle, Stonehenge, and Unexplained Places
Mystery Hunters: The Bermuda Triangle and Other Danger Zones
Making Headlines: The World's Most Shocking Secrets and Mysteries
Pivotal Presidents: Profiles in Leadership: Lyndon B. Johnson
Mystery Hunters: Fakes and Hoaxes
Understanding the Paranormal: Investigating Bigfoot, the Loch Ness Monster, and Other Cryptids
A Visual History of the World: A Visual History of the World's Enduring Mysteries
Understanding the Paranormal: Investigating Miracles
End of Days: An Encyclopedia of the Apocalypse in World Religions
Understanding the Paranormal: Investigating Angels and Demons
Cryptography: Code Making and Code Breaking: Cyber Attacks, Counterattacks, and Espionage
Climate Change: An Encyclopedia of Science, Society, and Solutions
Mysteries of History: Mystery of the Nazca Lines
Mysteries of History: Mystery of the Mary Celeste
Mysteries of History: Mystery of the Sphinx