Originally Posted by HarryT
An omnibus edition of the "Paratime" stories of H. Beam Piper which are in the public domain. These stories concern the Paratime Police, a law enforcement organisation from a parallel world which has learned how to move between timelines. They jealously guard the secret, even as they mine other worlds for their resources.
The stories in this omnibus are:
1. Genesis (some do not consider this to be a part of the series).
2. Police Operation.
3. Last Enemy.
4. Temple Trouble.
5. Time Crime.
Lots of illustrations, hence the large file size.
I don't consider Genesis to be part of the Paratime series, either, but it's good to have.
The missing parts are the "Lord Kalvan of Otherwhen" stories. Ace still has the rights to the novel, but those origianlly appeared as novelettes in Analog magazine, under the titles "Gunpowder God" and "Down Styphon!". I don't know the rights status of those offhand. It's possible they might become available.
Should you be so inclined, there are a couple of other Piper omnibuses you could consider. One would be the stories not part of the Paratime or Federation universes.
Another would be his collaborations with John J. McGuire. _Lone Star Planet_, _Null ABC_, Hunter Patrol_ and _The Return_ are all available at Project Gutenberg.
There is also his mystery, _Murder In the Gun Room_, but that would be a stand alone.