For people working in Developer Relations/Developer Advocacy/Tech Evangelism, the author (Chris Heilmann) is a person who does not have to be introduced.
This is indeed a handbook. It contains a lot of actionable advice, checklists, best practices, and opinionated guidelines from the author, who worked for decades in the IT industry in a given role.
And as the author stated - even though initially, this book filled a massive gap in the concept of Developer Relations (~2008), it's still relevant, actionable, and worth recommending position. Especially if you are in the DevRel world. And if you are not working in that role - the first chapter contains an excellent explanation of what Developer Advocacy is and why it matters (https://developer-advocacy.com/what-i...).