How old was the Doctor when he left Gallifrey? How many days duration is The War Games? When are the UNIT stories set? Is Revenge Of The Cybermen set before or after Earthshock? When does The Five Doctors take place within each Doctor's time-stream? Did the events of Terror Of The Vervoids really occur? Which Doctor was responsible for launching the Nemesis into space? Is the Doctor half-human? These question and more are examined in TIMELINK — an in-depth exploration of the complex continuity of the world's longest-running science-fiction television programme.