10/10 content, you will not find a better resource for system design elsewhere, including the 2 educative system design courses. The first half of this download is the volume 1 of the book which is great for beginners. The volume 2 starts at chapter 17 and the volume 2 is wayyyy more detailed than volume 1. Volume 2 basically became a full blown practical version of the famous DDIA/Designing Data Intensive Applications book by Martin Kleppmann, along with a ton of reference materials. Volume 2 is a must read even if you're not looking to prep for system design interviews, it will improve you as a dev.
Volume 2 is in-depth and written in a way that it follows the system design approach written about in the SRE books released by Google (
https://sre.google/books/), there is no other system design resource I know of that does it.