After my talk to Categories and Companions on Thurs 10 Jun 2021 about Mackey functors, one of the questions was whether I knew about the recent work on Mackey 2-functors. No I had not. Soon after that, Mathematical Reviews asked me whether I would be willing to review the book referred to in the title of this talk. I agreed and now would like to give some idea of what the book is about. (The talk is dedicated to the memory of Jean Bénabou whose concept of bicategory and example of spans are essential to the book.)