If you’ve been following Baeldung for a while, you know we publish a lot of extensive guides on Spring and Boot. 
I’m always happy to hear from readers who’ve used Baeldung to solve a tricky bug or learn how to work with one of the Spring projects.

But to really get a deep understanding of a subject, a structured, guided course is a better way to go.
This is why I’ve put well over a decade now into developing, consulting, and writing about Spring into creating my courses:

• The “Learn Spring” intro course - the best choice if you're just starting out with Spring and with Boot
• The "REST with Spring Boot" course focuses on building a solid REST API
• The “Learn Spring Security” course covers securing an application with Spring Security, from the core of the framework through to OAuth
• And “Learn Spring Data JPA”  - my first text-based course on data access with Spring Data JPA

Usually, students pick based on what they need to focus on first, or go with All Access and then go through the material in order. 
All courses are 33% until this Cyber Monday.

Hope this helps,
Cheers,
Eugen