Magical Beasts opens with a recounting of how early in humanity's existence the world was locked in an Ice Age. Humans feared the animals and worshipped the Cave bear. Time passed and the cave bear perished but other beast gods remained such as Cernunnos. The gods of Egypt were beast men and the Greeks spoke of their gods disguising themselves as animals. There are other examples such as Chiron; a centaur, he was hailed as the divine beast. There came the day, however, that Pan the goat god died and the beast gods' decline began. This was seen in how animalistic Fomorians of Ireland had lost their magic and were forced to ruling with brute force. They and Balor, their king, were routed by his grandson Lugh of the Long Hand, champion of the ascendant Tuatha de Danaan. Magic was dying as Europe Christianized but there were other places in the world such as Asia where magic yet held sway and dog men, monopods, and Blemmyes.

It also recounts that many flying animals, both mundane and magical, commanded respect for reason that they were able to escape the mundane world by flight. Pegasus, the Roc, Simurghs, Firebirds, the Phoenix, and even ordinary birds like the Raven in mythology and the robin were revered. Other flying animals were also known such as Griffins, Harpies and Tengus.

Of all magical beasts, however, Unicorns were the most respected. It epitomised beauty and purity but courage as well because it would never let itself be taken alive. Its cousins included China’s Ki-lin and the Persian Karkadann which, unlike their European counterpart, respectively embodied only gentility or ferocity. All however could be tamed by maidens. Unicorns' horns also had the power to cure poison and disease; in their desire to obtain the horns, humans drove unicorns to extinction

The text mentions other beasts such as the manticore, mermecolion, baromets, basilisk, and peryton.