While the title story might deserve an extra half star, the companion piece is enough weaker that it only averages three.
Legion of Time is a captivating story about alternate futures and probability. It was one of the earliest SF stories to explore the implications of what we now call quantum mechanics. The story revolves around a version of the observer effect and a time-travel version of Schrodinger's cat. An unfortunate scientist, by watching a horrific future from the past, unknowingly helps cause it. Undoing this requires time travel, unraveling alternate futures, and a host of other exciting elements, making it a lot of fun.
The second story, After World's End, is very dramatic and sweeping in scope. However, I had difficulty believing a word of it. The drama all hinges on a safety measure not being employed until humanity is almost wiped out. Billions of lives are lost because someone says "nah, I don't think I'll destroy the robot tyrant until absolutely everything lines up with this vague prophecy." The story wasn't as trite when it was written as it seems now. The basic idea of an inventor creating a robot so advanced that it doesn't need humanity and without bothering to program in safeguards is a common one. Another flaw, besides the safeguard issue, is that such an advanced robot would succumb to so many of the flaws of an ego-driven human tyrant.
Still, both stories are enjoyable Golden Age science fiction adventures and very quick to read.
Fun short novel about a regular Joe whose fate will determine whether the future will be a Utopia, or a dead world ruled by an evil queen. It is very pulp and was written in the late 30s. I still have to read After Worlds End, the "second half" of the book. Jack Williamson is one of my favorites of the old school science fiction writers. His works are full of imagination and creativity. In this short novel, the story of the regular Joe is both exciting and thought-provoking. The description of the possible future, whether it is a Utopia or a world ruled by an evil queen, makes readers wonder about the direction of human development. I am looking forward to reading the "second half" of the book to see how the story will unfold and what kind of ending it will have.