The question
I am seeing both the Official Study Guide (OSG) and the All-in-One book. Which one do people actually use? It is confusing to have two different sources claiming to be the best for preparation.
Verified summary
The (ISC)2 Official Study Guide is the primary source authored by the certifying body, whereas the All-in-One series is a third-party publication designed as an alternative study resource.
1 answer
The confusion stems from a misunderstanding of publisher licensing; (ISC)2 publishes the Official Study Guide, while All-in-One is a third-party resource authored by Shon Harris and successors. You must utilize the official text if your objective is strict alignment with the current Exam Outline.
