For anyone entering the world of mainframe programming, the (published by Wiley ) is the definitive guide to understanding, debugging, and maintaining COBOL programs. Core Curriculum Highlights
Rewriting decades-old, battle-tested COBOL mainframes is extraordinarily expensive and inherently risky. As a result, maintaining and updating legacy systems is an evergreen career path. "COBOL for the 21st Century (11th Edition)": A Deep Dive
While COBOL started as a procedural language, this edition covers the syntax and logic required for Object-Oriented COBOL, allowing it to interface with modern Java or C# environments.