I asked my friend if it was still valid, just wanted some confirmation as I know the ACT doesn’t change much compared to the SAT.
Ythe 3rd edition is the most recent edition of the Red Book.
It has 5 tests in it.
The writing prompts have changed since the book was publised.
There are some changes in the structure of the science section, but same number of questions.
There is a dual passage option in reading that you will not see in the Red Book.
Math has probability and stem a leaf charts.
I would use this book and also recent released tests to study.
If you need more details, you can PM me.