The Eight Doctors (1997) by Terrence Dicks is a passable Doctor Who novel that uses the Doctor Who story of revisiting past reincarnation. It is not nearly as good as the Five Doctors. It’s interesting to Who fans mainly because it is a regeneration visitation story. It’s the first book of the eighth doctor, Paul McGann. It’s not nearly as good as the better novels and radio plays that came later that led to the resumption of the TV series.