tomorrow. it's called "three days in moscow: ronald reagan and the fall of the soviet empire." bret baier joins us tonight. hey, bret. >> hey, tucker, thanks for having me. >> tucker: doug brinkley, one of the most famous, may be the most famous reagan historian calls this "one of the best and most essential books ever written about ronald reagan." i'm impressed. >> and i didn't even pay him. >> tucker: it's amazing. three days. you sort of boiled down the pivotal moment to three days.ng what three days? >> it's the three days of the fourth summit between reagan and gorbachev where reagan goes to moscow and he meets with gorbachev. they are finalizing the nuclear arms treaty, but he also gives an uncovered and overlooked for the most part speech to moscow state university students and takes q&a from them. we used the three days to jump back and look at how reagan getf to this point and really leads to the seminal moment of the cold war coming to an end, the