Triplanetary

E. E. "Doc" Smith's classic space opera Triplanetary has been available from Project Gutenberg (and ManyBooks) for years, but they just updated it. And don't forget, this is the original magazine version from the pages of Amazing Stories (January, February, March and April 1934) and not the later Fantasy Press version which was retconned into the Lensman series. So if you've only read the revised version you might want to revisit this ripping tale of super-science, space pirates and alien invaders.

(Covers by Leo Morey)