A user seeks to self-study precalculus before entering AP Calculus, specifically looking for a mathematically rigorous book that minimizes applications and calculator reliance. Recommendations include Israel M. Gelfand's "Trigonometry" and "The Method of Coordinates," along with "Principles of Mathematics" by Allendoerfer. The Larson and Hostetler "Precalculus" 4th edition is noted for its thoroughness, providing a solid foundation for calculus, although it may not have been fully appreciated during initial studies. Users emphasize the importance of understanding trigonometric identities and functions, as they are crucial for calculus. Overall, it's suggested that a strong math background, particularly in algebra II, will facilitate the transition to calculus, and various books can adequately prepare the user for this challenge. The Axler book, "Precalculus: A Precursor to Calculus," is chosen for further study.