Acknowledgments

A book that bridges introductory COBOL instruction and enterprise-grade practice draws on the knowledge, generosity, and experience of a community far larger than its authorship. We owe deep thanks to the many individuals and organizations whose contributions made this book possible.

The COBOL Community

Our foremost thanks go to the global COBOL community -- the programmers, systems analysts, architects, and operations professionals who maintain the systems that the world depends on. Many of you reviewed early drafts, shared production war stories, corrected our explanations, and pushed us to address the topics that actually matter in the enterprise rather than the topics that are merely academically interesting. Your insistence on practical relevance shaped every chapter for the better.

We are particularly grateful to the COBOL professionals who shared detailed accounts of production incidents, debugging sessions, modernization projects, and architectural decisions that became the basis for our case studies and running examples. The characters of Maria, Derek, Priya, James, Sarah, and Tomas are composites, but the experiences they represent are real -- drawn from the collective wisdom of professionals who trusted us with their stories.

The GnuCOBOL Project

The dual-platform approach that defines both this book and its predecessor would not be possible without GnuCOBOL. We owe special thanks to Simon Sobisch and the entire GnuCOBOL development team for maintaining a free, open-source COBOL compiler that makes the language accessible to learners worldwide. Simon's responsiveness to our technical questions and his review of our GnuCOBOL-specific content were invaluable once again.

GnuCOBOL's ability to run on personal computers -- Windows, macOS, and Linux -- removes the single largest barrier to COBOL education: the assumption that learning COBOL requires mainframe access. Every student who completes this book on a laptop owes a debt to the GnuCOBOL project.

IBM and the Z Ecosystem

We gratefully acknowledge IBM's contributions to COBOL education and the mainframe ecosystem. The IBM Z Xplore program provides essential access to z/OS environments for students working through the enterprise-focused chapters of this book. The IBM Enterprise COBOL development team's compiler documentation and redbooks served as critical reference material, particularly for the chapters on DB2, CICS, and IMS.

The Authors of Learning COBOL Programming

This book stands on the foundation laid by Learning COBOL Programming (TechLegacy Press, 2026). The pedagogical approach, the dual-platform philosophy, the exercise tier system, and the commitment to production-relevant instruction that define this volume were established in that predecessor. We thank the authors and contributors to that work for creating the foundation on which this intermediate volume builds.

Grace Hopper and the CODASYL Committee

We honor the memory and legacy of Rear Admiral Grace Murray Hopper and the CODASYL committee, whose vision of a readable, portable, business-oriented programming language created the foundation on which six decades of enterprise computing have been built. Every chapter of this book is an extension of the idea that programs should be comprehensible to the people who depend on them.

Technical Reviewers

Our technical reviewers devoted hundreds of hours to testing code examples across both GnuCOBOL and IBM Enterprise COBOL, verifying the accuracy of our DB2 and CICS content against current platform behavior, challenging our architectural recommendations, and ensuring that our advice reflects current enterprise practice rather than outdated convention. Their combined experience spans banking, insurance, government, healthcare, and retail -- the full breadth of the COBOL ecosystem. The remaining errors are entirely our own.

Our Publisher

We thank the team at TechLegacy Press for their continued commitment to comprehensive COBOL education. Their belief that the world needs not just an introductory COBOL textbook but an intermediate one -- and their willingness to invest in the scope and depth this subject demands -- made this book possible.

Family and Supporters

Finally, we thank our families, partners, and friends, who endured another round of long hours, missed weekends, and dinner-table debates about VSAM access patterns and CICS pseudo-conversational design. Your patience and support sustained us through a project that grew larger and more demanding than any of us anticipated. This book is dedicated, in no small part, to you.

To every COBOL programmer who has ever been handed a 10,000-line program with no documentation and told to "just figure it out": this book is for you.