My favorite although quite short is the heart-pounding “Reagan’s War”
bump.
Ronald Reagan... Dinesh D’souza..
the classic, authoritative biographies are the volumes by Lou Cannon. they’re by far the best if you want your friend to get a complete, full view of who Reagan was and how he fit into his times. Richard Reeves’ and Edmund Morris’ works are also highly respected, and while not nearly as authoritative as Cannon’s might be more accessible, depending on your friend’s reading habits.
regardless, it’s best to advise your friend to read one of works by a respected author (Reeves, Morris and Cannon are all highly distinguished scholars) rather than a blatantly partisan, narrowly focused work. so long as the writer is intellectually honest, it’s definitely more likely to leave your friend with a genuine appreciation of Reagan’s life and his political accomplishments.
“Governor Reagan” by Cannon is very good. “Reagan’s war” is a great study of his life-long fight against communism.
While not strictly a biography, I think you learn more about who Reagan was from Paul Kengor’s “The Crusader” than from any pure bio out there. It focuses on his lifesaving job, his Hollywood anti-communism, and of course, the Cold War. So you don’t get much about Governor Reagan, or about Nancy.
Peggy Noonan’s “When Character Was King” is quite good.
SnakeDoc
Don’t forget “Reagan in his own hand”. Dispels any of the myths about his intellectual abilities - contrary to what the jerks in the Democrat party at the time ( I include the Fourth Estate in that collective phrase - pun intended) may have said.