A Practical, Systematic Guide to Finding and Fixing Bugs Faster, from Local Code to Production

Read before you buy: the PDF here is a free sample — the first 20 pages of the 415-page book (payments, sales and reviews on this demo site are sample data). Get the full e-book at thenexbooks on Gumroad.

Every developer debugs. Almost nobody is taught how.

We learn languages and frameworks in courses, then spend a large part of our working lives staring at behavior that makes no sense — changing things at random, adding print statements everywhere, and hoping. The developers who seem to find bugs "by instinct" are actually doing something systematic, very quickly. This book teaches you that system.

You will follow one realistic team through ten memorable bugs at Marigold Pantry, a fictional grocery-subscription service: Auckland customers who see the wrong delivery day, rare double charges, a worker that slowly runs out of memory, an order page that crawls for loyal customers, a flaky checkout test, totals off by a single cent, and more. For each one you learn the technique that finds it fastest — and how to make sure it never comes back.

• 415 pages · 28 chapters + 4 appendices · practice exercises in every chapter
• A systematic debugging method you can apply to any bug in any language
• Reproducing bugs reliably, reading stack traces and logs, and shrinking problems to minimal examples
• Debuggers, conditional breakpoints, logpoints, and logging done right
• git bisect and binary search, tests as debugging tools, property-based testing
• Logic, state, data, time-zone, money, configuration, and dependency bugs
• Race conditions, deadlocks, async pitfalls, heisenbugs, and flaky tests
• Memory leaks and heap snapshots, CPU and I/O profiling, and N+1 queries
• Debugging across HTTP, networks, and distributed systems
• Observability, production incidents, browser DevTools, and database query plans
• Using AI assistants well — and verifying what they tell you
• Writing debuggable code, blameless postmortems, and a team debugging playbook
• Examples in Python, TypeScript/JavaScript, and SQL; techniques for any language

Table Of Contents

Part I — The Debugging Mindset

• Ch 1 · Why Debugging Is a Skill: A Systematic Method for Finding Bugs
• Ch 2 · Reproduce First: Turning Vague Reports into Reliable Reproductions
• Ch 3 · Reading Errors, Stack Traces, and Logs Carefully
• Ch 4 · Hypotheses and Experiments: Debugging as Applied Science
• Ch 5 · Shrinking the Problem: Isolation, Minimal Examples, and Delta Debugging

Part II — Core Tools and Habits

• Ch 6 · Debuggers in Depth: Breakpoints, Stepping, Watches, and Conditional Breakpoints
• Ch 7 · Print Debugging and Logging Done Right
• Ch 8 · Binary Search Everything: git bisect and Divide-and-Conquer
• Ch 9 · Tests as Debugging Tools: Failing Tests, Characterization Tests, and Property-Based Tests
• Ch 10 · The Human Side: Rubber Ducks, Breaks, Pairing, and Asking Good Questions

Part III — Common Bug Families

• Ch 11 · Logic Bugs: Off-by-One Errors, Boundaries, Null and Undefined
• Ch 12 · State Bugs: Mutation, Aliasing, Caching, and Stale Data
• Ch 13 · Data Bugs: Encoding, Floating Point, Money, Dates, and Time Zones
• Ch 14 · Environment and Configuration Bugs: "It Works on My Machine"
• Ch 15 · Dependency and Build Bugs: Versions, Lockfiles, and Toolchains

Part IV — Hard Bugs

• Ch 16 · Concurrency Bugs: Race Conditions, Deadlocks, and Async Pitfalls
• Ch 17 · Heisenbugs and Flaky Tests: Taming Nondeterminism
• Ch 18 · Memory Bugs: Leaks, Bloat, and Heap Analysis
• Ch 19 · Performance Bugs: Profiling CPU, I/O, and Hot Paths
• Ch 20 · Debugging Across Boundaries: HTTP, Networks, and Distributed Systems

Part V — Debugging in Production

• Ch 21 · Observability for Debugging: Structured Logs, Metrics, and Traces
• Ch 22 · Production Incidents: Triage, Mitigation, and Gathering Evidence Safely
• Ch 23 · Frontend and Browser Debugging: DevTools, Network, and Rendering
• Ch 24 · Database and Query Debugging
• Ch 25 · Debugging with AI Assistants: Using Them Well and Verifying Their Answers

Part VI — Prevention and Learning

• Ch 26 · Writing Debuggable Code: Assertions, Errors, and Design for Diagnosis
• Ch 27 · Postmortems and Bug Journals: Learning from Every Bug
• Ch 28 · Case Study: Hunting Down Marigold Pantry's Worst Bugs

Appendices

• App A · Debugging Cheat Sheet
• App B · Tool and Command Reference
• App C · Debugging Checklists
• App D · Glossary

WHO IT IS FOR
Junior developers who want a reliable process instead of random changes; experienced developers who want to get faster at hard bugs; QA engineers who write precise bug reports; SREs and on-call engineers who debug live systems; and tech leads who want their teams to learn from every bug.

FORMAT
PDF (A4), 415 pages, English, clickable table of contents and PDF bookmarks. 1st Edition, 2026. Published by thenexbooks.

All trademarks mentioned belong to their respective owners. This book is independent and not affiliated with any tool vendor.

Book details