The discussion centers on finding calculus textbooks that bridge the gap between the levels of Stewart or Thomas and Spivak, Courant, or Apostol. Suggestions include Keisler's book, which employs hyperreal numbers to simplify concepts, and Buck's book mentioned by the Math Sorcerer on YouTube, which leans towards advanced calculus. Other recommended titles include Edwards and Penney's first edition, Lipman Bers' Calculus, early editions of Courant and Lang, and Cruse and Granberg. The conversation emphasizes the variability in editions of popular texts and suggests browsing university libraries for a broader selection. Additionally, it notes that while Apostol is rigorous, it can be more accessible for learning calculus compared to Spivak.