The book has been split into three parts.

Part I, SLO Development: This should be considered mandatory reading if you’re going to implement an SLO-based approach to reliability—it outlines the concepts, philosophies, and definitions you need to be familiar with to take your first steps. The chapters in this part explain what the various components of SLOs are, how to use them successfully, why they work, and how you can make them work for you.

Part II, SLO Implementation: Here you’ll start to hear from some of my brilliant friends from across the industry. While Part I helps you learn how things work, Part II is much more practical in nature. Together we’ll help you tackle some of the more complicated aspects of implementing an SLO-based approach, including the math you need to have meaningful service level indicators (SLIs) and accurate SLO targets, the most useful alerting for your team, as well as how to get buy-in company-wide.

Part III, SLO Culture: This part discusses how you can make sure that adoption of an SLO-based approach to reliability for your team, organization, or entire company can be engaged with in the most efficient manner. Too many people think of implementing SLOs as “something you do,” in the sense that it’s a singular goal you can check off a list. That isn’t how all of this actually works. SLO-based approaches encourage thinking about the reliability of your services in a different and more accurate way. The chapters in this section ensure that you can implement SLOs in the best possible way, and use the concepts behind them for better communications across teams.

Additionally, the final chapter, Chapter 17, Reliability Reporting, brings everything to a close and contains some of the most useful advice in the entire book. Make sure you don’t skip over that.

To make the most out of the book, I truly hope you read every chapter. The chapters in the first section should be read in order, but the last two sections can be read in whatever order best addresses the needs of your situation. You don’t need to read every chapter consecutively; I hope this book will be as much of a reference for you in the future as it is an educational tool to get you started. It was designed to be both a primer and a source for you to return to again and again.

No matter what your situation is, or what your goals are, I hope at the very least you can walk away from this text remembering the lessons Molly taught us. While this book is mostly about computer systems, the general philosophies are broadly applicable: you can’t be perfect, no one needs you to be perfect anyway, it’s too expensive to try to be perfect, and everyone is happier at the end of the day if you embrace this.