With a fiction book, it is a very rare occurrence that I would quit reading it. The book would have to irritate me to such an extent that reading it is more stressful than my job is. I do not have a criteria for non-fiction, however. This book being what it is, I do not feel bad for putting it down forever. It was written in 1961, so the science behind it is old, and I suspect a lot of the theories are ones scientists may have moved past at this point. So, it's not really educational. The writing style is boring and over-simplifies everything. So, it's not entertaining. Once I realized this, I decided to quit reading it. Unless you're really interested in the history behind the book, I wouldn't recommend it.