Originally Posted by Fledchen
Galactic Derelict is part of the series, but it's not on Project Gutenberg. I don't know if that's because it's still in the works at P.G. or if the copyright was renewed and it's not eligible.
It is interesting because these books were all written fairly recently...
1. The Time Traders
2. Galactic Derelict
3. The Defiant Agents
4. Key Out of Time
...and Norton died in 2005 according to fantasticfiction. So, they should all still be in copyright. I know that Time Traders is in the baen free library. Perhaps others were on the Baen CDs?