Lethe alpha literally means "un-forgetfulness" or "un-concealment". Lethe, the river of forgetfulness, was one of the five rivers of the Greek underworld, the other four being Styx, Acheron (the river of sorrow), Cocytus (the river of lamentation) and Phlegethon (the river of fire). According to Statius, it bordered Elysium, the final resting place of the virtuous. Ovid wrote that the river flowed through the cave of Hypnos, god of sleep, where its murmuring would induce drowsiness. The shades of the dead were required to drink the waters of the Lethe in order to forget their earthly life. In the "Aeneid", Virgil
The Complete Guide to Prehistoric Life then divided into three parts by era, first of which is The Rise of Life, which covers the Precambrian and the Paleozoic Era, and lasts from pages 8 through 49. The second part, The Age of Reptiles, covers the Mesozoic Era, and lasts from pages 50 through 143. The third and final part, The Age of Beasts, covers the Cenozoic Era, and lasts from pages 144 through 206. The book concludes with a timescale of life on earth, tree of life diagrams, and the acknowledgements and index. The Complete Guide to Prehistoric Life The Complete Guide to Prehistoric Life is