As the author Kaplan explains, once a horizon was explored and demonstrated that it offers no real risks of monsters like the forest, over time new horizons would arise like the ocean or space, about which little would be known, thus giving man further material to create a new concept of monster. My only criticism of the book is that in some cases author Matt Kaplan illustrates a negative attitude or bias towards certain monster concepts, often letting the reader know that he believes a particular belief is absurd. For example, he seems to illustrate his bias in the volcano discussion by stating, "As stupid as Vulcan is, it and Dante's Peak play with real unknowns associated with when and why earthquakes and volcanic eruptions occur." Although to a rational historian some of the monster concepts included in this book may seem far-fetched, it is important for a historian to always keep an open mind when analyzing sources, even if they initially appear to be beyond the scope of the credible. This statement alone illustrates this, although something may seem out of the ordinary