The ARRL books for extra will not cover the same material as the lower licenses. There is of course some overlap on topics. But a large part of each study book for each license will cover the specific limitations of each license and regulations related to that license.
Discussion
In particular the study questions in the “Extra” license are unique to the specific exam for that license. And the same is true for each book for its respective license.
Thanks for the confirmation. This is what I suspected based on cost and page count. Is there a reference that has all three; eventually want to pursue all of them.
Not that I am aware of. I do not believe ARRL has such a resource. It may exist somewhere else. The licenses do have to be taken in order. And the question pool does change over time. So it is a bit of a risk putting all three into a single resource. With life getting in the way occasionally even with a similar intention I have only gotten through my general license so far. I have the extra study book which I got at the same time as the others but the question pool in the book is out of date. Even though most of the content will carry over.