Courant & John's "Introduction to Calculus and Analysis, Volume II" is part of a two-volume series, with the second volume divided into two parts in newer editions, totaling three volumes including the first. The text is noted for its substantial size and applications to physics. Users express high regard for the first volume, praising its depth and rigorous approach to calculus. The book stands out for its engaging style, moving away from traditional dry formats to more intuitive explanations and proofs. Exercises are highlighted as particularly challenging and valuable. Recommendations favor the "Courant & John" version over the original "Courant" for its superior structure. Overall, the series is considered an excellent resource for mastering calculus.