When Shadows Fall - L. Ron Hubbard - Bog

Star Trek’s Captain Kirk has a kindred soul in Lars the Ranger, a commander of his own star fleet. But whereas Kirk’s mission is to boldly go where no man has gone before, Lars is boldly going where other men are—in a desperate attempt to save his home planet … Earth. He’s not exploring the final frontier. He is our last hope.
Earth is way past global warming. ItΓÇÖs totally friedΓÇöan environmental disasterΓÇöand most of its inhabitants have cut out for greener pastures, colonizing distant worlds. Lars leads an expedition across the galaxy to visit those worlds in hopes that he return with the resources needed to bring Earth back from the brink of extinction.
But Lars has apparently failed. A mammoth fleet of mysterious starships are descending on the third planet from the sun. Is Earth history? Yes … and that may just be its saving grace.
Also includes the science fiction adventures, Battling Bolto, the story of a giant, con man whoΓÇÖs running an interstellar scam, while the biggest trick of all lies right under his nose; and Tough Old Man, in which an aging constableΓÇÖs lack of feelings is not a matter of insensitivity, but of a secretΓÇöand surprisingΓÇöside of his character.