Why Study with Official ACT® Prep Guides? For more than 60 years, the ACT test has helped millions of students evaluate their academic skillsets and overall college or university readiness. Wiley is proud to publish the Official ACT® Prep Guide and separate Subject Guides in partnership with ACT so you can study confidently with materials that help you: Understand official testing format, timing, and overall procedures. Answer questions efficiently. Learn exactly what you need to know to succeed on test day.