The definitive guide to the Scaled Agile Framework. It contains the important topics that you will have to dig to get on scaledagileframework.com and is very readable. I especially recommend it to everyone that wants to pass the SPC exam.
Although agile is the de facto method of developing technology products in most companies, it's focus has been on product delivery. The aim of this book is to teach product teams how to discover solutions that will delight customers. It has many case studies of successful product managers at Google, Netflix, and Microsoft and how they were able to leverage the talent of their engineers to discover solutions that dramatically impacted their bottom line.
Organizing user stories in such a way that they will tell the bigger story is the aim of this book. Every product team (especially the product owner) must learn how to leverage story mapping to keep the customer and the development team in sync. It is my go-to technique for breaking down large epics.
The authors provide 23 recipes for conducting agile retrospectives. What I find useful is its step-by-step explanation for conducting the retro exercise that will surface the results you're looking for.