Modernizing Drupal 10 Theme Development

The book is written for frontend and backend developers and someone who is somewhat familiar with Drupal. It does attempt to explain some of the basic concepts such as nodes, content types, and taxonomies, but I felt it was not clear enough to someone who is completely new. To be fair, such a user would probably pick up a generic Drupal book rather than a book specializing in theming. It's divided into three parts and you can pick the chapters that make most sense to your needs. The first part is an introduction to setting up the development environment and theming basics. Chapters here might be useful to you if you are new to Drupal. The second part covers advanced topics under component-driven design and more. The third part provides a quick coverage of writing a decoupled Drupal site.

Drupal needs a bit of site setup to be done before any meaningful theming and the author just provides a code repository to begin with. We continue building on this code as we learn concepts. The choice of local development tools mentioned in the book is good. Just be careful of using the configuration as-is unless you know what you're doing. The tools for frontend itself are a little dated but still widely used. I wish the book had covered tools such as vite but maybe that's too cutting edge? The book instead covers fairly standard tooling with webpack, BackstopJs, Browsersync, stylelint, phpcs, and more.

Broadly speaking, the book covers various theming related topics beginning with the asset library system in Drupal, how a page is rendered, design systems (using Storybook), overriding templates, theme suggestions, before moving on to working with specific type of components in Drupal (such as header, footer, views, blocks, etc). In each of these cases, the author covers enough detail for someone not familiar to PHP and Drupal. It's a fairly decent coverage of the entire theming system in Drupal. The book also covers relatively newer concepts such as using the components module and Single Directory Components. It also went on to describe advanced use cases such as making the themes configurable, accessibility, writing custom twig functions, and finally decoupled Drupal websites.

Personally, I found that accuracy and nuance improved in the book once it moved to advanced topics. Overall, I recommend this book as a good reference as you learn theming. But it's a good idea to have at least some basic knowledge of Drupal or your experience may vary.