^A I prefer footnotes to endnotes because footnotes allow you to glance at the text without having to lose your place in the book. I will generally be including three kinds of information in footnotes: (1) parenthetical comments that are too long to be included in parentheses (such as the etymology and location of brain structures); (2) cheeky jokes and stories that I can’t resist including but would disrupt the flow of the book if I included them in the main text; and (3) technical details when there are subtle, second-order effects that need to be noted but are too complicated for those without the necessary background. The book should be readable without the footnotes, but I hope the footnotes will add an extra dimension for those who want more depth.