Although portions of Triplanetary were written earlier, they were not originally part of the Lensman story and were only later revised to connect them to the rest of the series.

Galactic Patrol introduces Kimball Kinnison, who will be the hero of the next three books - Gray Lensman, Second Stage Lensmen and, to a lesser extent, Children of the Lens.

Organized pirates, known as Boskonians, have gained a great advantage with a new type of space drive, making their ships far faster than anything the Patrol can build.

Kinnison is the first Lensman to be accepted for further training by the Arisians, and leaves weeks later many times stronger and with numerous additional capabilities.

Using the information that Kinnison brought back about the new space drive, the Galactic Patrol quickly rebuilds its ships and goes out pirate hunting again.

New York Times reviewer Basil Davenport declared that Galactic Patrol was "far above the interplanetary cowboy and Indian school" because of "Smith's ability to create planets with truly original climates and inhabitants" as integral parts of his story.

[1] P. Schuyler Miller, reviewing the same 1950 edition favorably for Astounding, declared that "What John Ford is to horse-opera -- Grade A, homogenized -- Doc Smith is to space-opera.