The books under the Introductory Books menu are recommended for those new to the subject of Dianetics and Scientology. The introductory books introduce concepts that are gone into in more depth in the more advanced books.
Scientology is a complex subject, so it’s helpful to learn the basic concepts so that more advanced materials make sense as you progress.
Dianetics: The Modern Science of Mental Health (DMSMH) is considered the cornerstone book for the subject of Dianetics. It describes Dianetics in detail and, if studied thoroughly, gives a person the understanding and ability to use the counseling techniques with another person.
Dianetics: The Original Thesis and Dianetics: The Evolution of a Science are much shorter than DMSMH. Both are great to get your feet wet in the subject, or to fill out your understanding if you’ve already read DMSMH.