| Doctor Who book | |
|---|---|
| Deep Blue | |
| Series | Past Doctor Adventures |
| Release number | 20 |
| Featuring | Fifth Doctor Tegan, Turlough, Mike Yates and UNIT |
| Writer | Mark Morris |
| Publisher | BBC Books |
| ISBN | ISBN 0-563-55571-8 |
| Set between | Warriors of the Deep and The Awakening (for the TARDIS crew) and between The Green Death and The Time Warrior (for the members of UNIT) |
| Number of pages | 249 |
| Release date | March 1, 1999 |
| Preceded by | 'The Wages of Sin' |
| Followed by | 'Players' |
Deep Blue is a BBC Books original novel written by Mark Morris and based on the long-running British science fiction television series Doctor Who. It features the Fifth Doctor, Tegan, Turlough, and members of UNIT, mostly embodied by Captain Mike Yates.
As with all Doctor Who spin-off media, its relationship to the televised serials is open to interpretation.
As a Fifth Doctor novel set in the Third Doctor's era, Deep Blue is notable for possessing a particularly complex chronology. To minimize confusion with later meetings between the Fifth Doctor and Brigadier Lethbridge-Stewart (Mawdryn Undead and The Five Doctors), Mike Yates, someone who never met the Fifth Doctor on screen, is used as the main UNIT contact. One of the chief points of interest in the work is how the Brigadier, Turlough and Tegan can appear together, both long before — and long after — they apparently met for the first time in Mawdryn Undead.