The discussion centers on the search for a mathematically rigorous book that covers both classical and quantum mechanics. It suggests that it may be more beneficial to use separate texts for each subject. For quantum mechanics, recommended books include "Quantum Mechanics" by Ballentine, although it is advised to read it as a third book after Griffiths and Isham. For classical mechanics, "Mechanics: From Newton's Laws to Deterministic Chaos" by Scheck is recommended for beginners, while more advanced readers might consider "Introduction to Mechanics and Symmetry" and "Foundations of Mechanics" by J.E. Marsden. The conversation emphasizes the importance of understanding measure and integration theory, along with functional analysis, to grasp the mathematical rigor in these fields. Additionally, "Introductory Quantum Mechanics" by Liboff is noted as a superior introductory text compared to Griffiths.