It's a book about Monster Hunter Tri. At the bottom right I can see that Mami had something to do with it, but I don't know any Japanese and Google translate isn't much help so I don't know what the connection is. Does this mean Mami has been playing Monster Hunter? (Playing with Mami would be pretty awesome, don't know if the servers are global though.) Did she draw something for this book? Have I totally misunderstood?