A couple of notes on Doctor Who "Expanded Universe" fiction:
-The canonicity of these, like that of Star Wars, is often debated. Wikipedia states their canon is 'unclear'. However it is worth nothing that several new series writers, including RTD himself, have written for the novel and audio lines.
-There have been several Doctor Who novel lines, although some are currently defunct. These include:
-The Target Novelizations, which adapted almost all serials of the show into novel form. They ceased production in the early 90s, with only the Douglas Adams and Eric Saward Dalek stories unfinished.
-The New Adventures, which featured the adventures of the Seventh Doctor post-SURVIVAL. Published by Virgin. The line also includes one Eigth Doctor novel and after the license was lost the line continued for some time afterwards featuring the adventures of novel-original companion Benny Summerfield.
-The Missing Adventures. Several novels that take place between classic series serials, many of which feature sequels to television stories.
-BBC Eigth Doctor Adventures, which continue the adventures of the Eigth Doctor between the TV movie and Rose.
-BBC Ninth Doctor adventures, featuring adventures set during the first season of the new series.
-BBC Tenth Doctor Adventures, featuring adventures set at this point during the second season.
-BBC Past Doctor Adventures, which serve the same function as the Missing Adventures.
I'll post a writeup on the audios and comics later.