<p>With an average ACT score of 27, you don’t have much chance of getting into the few colleges that factor ECs into admission. Those are the most competitive colleges – places like Harvard and Amherst, colleges where accepted students average scores are in the 30s.</p>
<p>I would not buy an ACT prep book by a high school student unless the student had scored at least a 35. There are plenty of reputable ACT prep books. There would be no reason to buy one by a high school student unless that student had an exceptionally high score.</p>
<p>I think that if what the OP is trying to do is increase his/her chances of getting into top colleges, it would be better if the OP spent their time raising their ACT score, not writing a book.</p>