Ultimate Guys' Body Book

I purchased this book in conjunction with a similarly reviewed girls body book. I gave both to my pre-teen (on the basis that if they learn about both genders then curiosity will be less likely to lead them into trouble). The comment from my pre-teen was that this book was really difficult to take in as the writing style was difficult to """"get in to"""". By that I believe they found it difficult to engage with the text. I have been asked to find one with language that is more easily understood and that has end of chapter activities and devotionals that are fun. The equivalent girls book was devoured in a couple of days.