This document provides a comprehensive overview of Architecture Design Records (ADRs), a crucial tool for documenting key decisions in software development. Initially coined by Michael Nygard, ADRs encapsulate the reasons and context behind these decisions, helping future developers understand the system’s evolution. Each ADR typically includes a title, context, decision, status, and consequences, and is stored in the project’s version control repository. For .NET developers, this guide recommends the dotnet-adr tool, and provides step-by-step instructions to implement ADRs in your project. By incorporating ADRs, teams can enhance communication and preserve a clear rationale for significant decisions.