The developer guide is the main developer documentation on Relatude CMS & E-commerce. It covers a wide range of topics you'll meet when developing solutions using Relatude.
A good foundation
Since the developer guide covers a wide range of topics, it can't go into detail on all of the topics. It's not meant to contain all possible documentation you'll need when developing using Relatude, but give you a good foundation to use the platform.
The API reference and resources section are meant to cover the needs for more in-depth information than what you'll find in this guide.