This book covers the technology and tradecraft a reporter would need to safely handle leaked data. I've worked in this area since 2009 and this is hands down the best resource I've ever seen - a comprehensive exposition on the methods with lots of easy to follow hands on exercises. I already knew about 80% of what Lee suggests, the things I personally found most valuable were the introduction to Docker Compose, as well as the Aleph and Dangerzone tools. I run a Substack where I publish on similar matters, I'm used to writing for those who've newly developed an urge to dig deeper, and Lee does an excellent job of picking starting points accessible to all, then building on them.