Book has always led his team to be a top competitor, as Notre Dame ranked 5th, 11th, and 5th again in the coaches poll during his three years starting. He played in the 2018 Cotton Bowl and the 2020 Rose Bowl, but lost both by more than two scores. Despite playing just one less game from 2019 to 2020, he had 14 fewer touchdowns, and 300 fewer yards. However, he has always been praised by teammates and coaches for his leadership and helped Notre Dame to the playoffs after a shortened offseason in a new conference. Despite the praise and team success, his ceiling is rather low and a lot of his production is often attributed to the system he played in. He won't be ready to start for several years and is likely going to fall to day 3, unless a team with few needs thinks they can develop him quickly. He needs a lot of work in multiple areas and if he ever does get the chance to start he may be a low tier starter.