It appears that there is no widely recognized book titled authored by Unmesh Joshi . However, Unmesh Joshi is a prominent contributor to the field of distributed systems and systems design, particularly through his open-source work on GitHub . His repository, SystemsDesignPatterns , is a comprehensive resource on distributed systems design patterns and is often cited by engineers and developers. If the PDF you referenced is derived from this repository or similar projects, the content is likely a collection of practical patterns, architectures, and case studies for building distributed systems.