Time Life Mysteries of the Unknown unexplained occult lot of 4 books cosmic time & space, UFOs

Lot of four books from the Time Life Mysteries of the Unknown series. These are The UFO Phenomenon, Time and Space, Cosmic Connections, Cosmic Duality.

These are in poor condition - these books have been well loved, marked with name and catalog numbers by former owner. Some books are water spotted, or discolored and yellowed. Looks like they've been carried out into the field! All have scuffing, cover wear, some soil.