Dreamstone Moon
Sam is on her own, but her distance from the Doctor doesn't make for a trouble-free life.
G
Genocide
Years after leaving UNIT, Jo Grant receives a plea for help from an old acquaintance. A palaeontological study of the earliest known humans is apparently under threat from a UNIT force led by a captain who does not officially exist. Investigating further, she begins to find herself out of her depth - and out of the twentieth century altogether...
R
Revolution Man
1967: The Revolution has just started. All you need is love - but the ability to bend space and time helps.
V
Venusian Lullaby
This is the one Doctor Who novel I would lend to non-fans.