This is one from the first set of covers Gaughan did for Pyramid paperbacks of the "Lensman" series; some later printings used the same art but it was clipped or shrunk - with white borders. While I also like his "psychedelic" set, I feel that this set best captures the classic "space opera"/epic sweep of the series.

Just when Kimball Kinnison is thinking he has completed his job and lopped off the head of Boskone, Mentor of Arisia breaks protocol to get him to think straight, and realize that his task is far from completed - Boskone had other tentacles which would be used to respond and attack. Just as the Patrol learned to improve their ships after capturing and examining a Boskone ship (superior at the time of Galactic Patrol), Boskone will be able to use negaspheres and "free" planets that the Patrol has demonstrated. Kinnison orders the reinforcement of the Sol system to withstand any possible attack - which comes all too soon.

Following a lead on a zwilnick, the Gray Lensman tracked a Boskonian agent to a previously unknown planet, home to the Matriarchs of Lyrane - mentally powerful, but fantastically non-cooperative, and they hated all males. Illona the zwilnick proved to be a storehouse of information about Boskonian life and methods, and the link to another unknown world - Lonabar, source of unique gems and a link to those in the highest ranks of Boskone. The alien second-stage Lensman, Nadreck of Palain VII, got the job of scouting Lonabar, and then Lyrane VII - once a connection with Lonabar was established. Kinnison gets a brainstorm and drafts the love of his life, Clarissa MacDougal, to become the first woman Lensman and be liaison to Lyrane II. She runs into a nest of the Overlords of Delgon, like-minded allies of the Eich.

Even though it was known that Boskone was by no means the prime mover in that dark culture which opposed Civilization so bitterly, it was still referred to as "Boskonia." Boskonia had the advantages of stealth and surprise, operating against precisely plotted objectives. Civilization had the Lens, and a massed purpose and morale that the whip-drivers of Boskone could not understand. The Lensmen came up with a 2-pronged attack: at the same time the main fleet of the Patrol moved in on the Second Galaxy to clear out the Boskone presence there, Kinnison had the task of infiltrating and moving up from within the ranks of the Tyrant Alcone of Thrale, who had taken over the duties and authorities ofthe Council of Boskone after its fall. And at the end, Kimball Kinnison and Clarissa MacDougal finally get married. [This was serialized in 4 parts in Astounding, beginning November 1941.]