This is van Vogt's first novel, put down in the 1940s.
Basically the Slan are a race of mutants created by a scientist in the late 21st century. They have two hearts, psi powers and posses super strength compared to humans.
Sounds fantastic, and perhaps if written today it could be, but van Vogt's clumsy over-elaborate ramblings spoil the flow. Where a few words would have done the job he seems to have consulted a Thesaurus!
I'm sure it must have been groundbreaking back then but I just found it tedious and a bit boring! I was glad when the last page came to be honest!
Which is odd because the only other van Vogt book I read, The Voyage of the Space Beagle, was superb, and gave rise, much later, to a certain alien life form brought to the screen by Ridley Scott et all....
Oh well...cant win em all...
Review: Ravencry by Ed McDonald
2 days ago