The star Mira was unpredictably variable. Sometimesit was blazing, brilliant and hot. Other times it was oddlydim, cool, shedding little warmth on its many planets.Gresth Gkae, leader of the Mirans, was seeking a betterstar, one to which his "people" could migrate. That starhad to be steady, reliable, with a good planetary system.And in his astronomical searching, he found Sol.

With hundreds of ships, each larger than wholeTerrestrial spaceports, and traveling faster than the speedof light, the Mirans set out to move in to Solar regionsand take over.

And on Earth there was nothing which would be capableof beating off this incredible armada—until BuckKendall stumbled upon THE ULTIMATE WEAPON.

JOHN W. CAMPBELL first started writing in 1930 whenhis first short story, When the Atoms Failed, was acceptedby a science-fiction magazine. At that time hewas twenty years old and still a student at college. As thetitle of the story indicates, he was even at that timeoccupied with the significance of atomic energy andnuclear physics.

For the next seven years, Campbell, bolstered by ascientific background that ran from childhood experiments,to study at Duke University and the MassachusettsInstitute of Technology, wrote and sold science-fiction,achieving for himself an enviable reputation in the field.

In 1937 he became the editor of Astounding Storiesmagazine and applied himself at once to the task ofbettering the magazine and the field of s-f writingin general. His influence on science-fiction since thenhas been great. Today he still remains as the editor ofthat magazine's evolved and redesigned successor,Analog.