The demand for developers skilled in Spring and Spring Boot remains strong, reflecting the frameworks' key roles in modern software development and the constant expansion of Java-based applications across industries. This technical guide to Spring Framework 6 and Spring Boot 3.0 employs a scenario-based methodology, systematically addressing enterprise-grade concerns, including TDD, security, and observability. The content progressively builds a complete application, with each chapter expanding specific components while maintaining a focus on production-ready implementation patterns. A companion GitHub repository provides complete source code, allowing readers to focus on critical concepts. The book's architecture progresses from fundamental Spring concepts through practical implementations of MVC applications, data persistence, REST/GraphQL APIs, reactive programming, and messaging systems, concluding with deployment strategies and emerging Spring technologies. All examples follow enterprise-quality standards applicable to real-world development scenarios.This book provides fundamental concepts for beginners starting on their journey with Spring and Spring Boot, enabling them to rapidly transition to developing real-world applications and services. It also serves as a valuable resource for Spring developers seeking to enhance their expertise with Spring Framework 6 and Spring Boot 3.0.