Some of the books HiLoBooks has already brought back into print are:
When the World Shook and The People of the Ruins have been abridged, but the other novels are complete. Note, that though these have been out of print for years, most of these are available as free ebooks through Gutenberg.org and other sites. But kudos to HiLoBooks for bringing these classics back into print and highlighting an often forgotten period of science fiction. Look for my review of The Scarlet Plague tomorrow.