The author shares insights into the motivation behind writing 'The Beam Book'. With a focus on the complexities of developing software for large-scale systems like Klarna, the author emphasizes the importance of organization and adaptability in writing about such a rapidly evolving subject. They mention a specific performance threshold (15ms) that can trigger significant operational issues, underlining the criticality of understanding performance in software development. Interest in the book is highlighted, with comments suggesting a desire for various formats, such as a Kindle edition.