I read this book, and I couldn't believe how much it explained about me!
Anyone who wants to understand human behaviour should read this book...
The glossary is great and I found the examples given in the book helped me understand how it relates to all people.
Also, if you like this, then you should also read "Self Analysis" which is very practical and you use the Dianetics processes in it.
Overall, Hubbard's style of writing makes it a great read and I can truly say I have improved my life from reading this!