A National Geographic Book.  This book, Brain, The Complete Mind, How It Develops, How It Works, and How To Keep It Sharp, by Michael S Sweeney, covers some of the new neuroscience discoveries, and includes, among much more information, the following.  It describes some of the major neurotransmitters.  According to an online search of “How many neurotransmitters are there?”  there may be from at least 60 to over 110 neurotransmitters.   On this page we learn something about how Helen Keller managed, and the thoughts of St. Thomas Aquinas on aspects of the working mind.  Scattered throughout the book are these sections on “Staying Sharp”.  This book has many other helpful features.  Near this sections is one describing how people think, in order to, for example, follow a recipe.  This page describes how nuns age.   This nicely illustrated book does indeed give “you greater insight into how your mind operates and how you can keep it sharp”.