One thing you notice looking at these early issues--the covers by Murphy Anderson featured amazingly iconic battles. A life-and-death chess match, a doorway to another dimension, and now a slaveship in outer space! Before Infantino, Adams, and Cardy came along and really ramped up the excitement quotient for DC's covers, these early JLAs must have just jumped off the spinner racks.
The story: "The Slave Ship of Space!" by Gardner Fox, Mike Sekowsky, and Bernard Sachs. An alien named Kanjar Ro uses his powers to force the JLA into helping him defeat his enemies, the respective rulers of neighboring powers.
He manages to freeze Batman and Snapper Carr in place and subdue Superman with a Kryptonite gas(!), drafting the rest of the JLA to help him.
Roll Call: Superman, Batman, Wonder Woman, Aquaman, Flash, Green Lantern, Martian Manhunter
Notable Moments: Kanjar Ro is considerate enough to provide a regular water supply for Aquaman(man, that magic wand thingy he has can do anything), and the Sea King repays him by being the one who grabs it out of Ro's hand once the JLA finds a way to defeat him.
At one point, Batman thinks to himself, "I wish Superman were here--he'd be able to rescue us!" One of Batman's less, er, confident moments.
Jerry Bails gets another letter printed, and no less than four readers suggest Superman and Wonder Woman get married!