Title: Skylark Duquesne
First published: June 1, 1980
Description: Skylark Series, Book 4 of 4

Dick Seaton & Marc DuQuensne are the deadliest enemies in the Universe--their feud has blazed among the stars & changed the history of a thousand planets. But now a threat from outside the Galaxy drives them into a dangerous alliance as hordes of strange races drive to a collision with mankind. Seaton & DuQuensne flight & slave side by side to fend off the invasion--as Seaton keeps constant, perilous watch for DuQuesne's inevitable double-cross.
Subjects: Fiction, science fiction, general, Fiction, Space flight, Space ships, American Science fiction