As a person Randall Munroe does many similar things as done throughout the book he wrote. The story is all Q and A's that have been asked to him, via website.
When I started to research him more I understood why the book was written the way it was. When he had worked for NASA he would become bored and doodle comics as a way to pass the time. In his book, nearly every page has at least one picture, big or small, on it. Also being a scientific theorist he basically used all of his knowledge to write the book as a whole. Without him becoming an S.T. he would have never written the book. The book shows the reader how certain scenarios would play out, and just how vast Randall Munroe's knowledge of science really is.
To put it simply, the book is Randall Munroe's life. He does the research for a living anyways. His job was to describe theoretical scientific problems which is what this book does, very well.