Interesting read.
The little book consists of 3 short stories by well known authors of Sci-Fi.
The third story 'Son of two worlds' by Edmond Hamilton was the longest, and also the best story in my opinion. There were a couple of problems with the writing though, (Like the needless repetition of character names) but the story idea and the description were well laid out. As far as the science bit in this story goes, one has to take it with a spoonful of salt. This was written years before the moon landing, and the author imagined that travel past the moon and reaching earth would be a matter of minutes. Still it was an enjoyable read.
The best written story in my opinion was 'Double Meaning' by Damon Knight. Some intriguing ideas, what one expects from a good Sci-Fi story. There were some things that culturally would definitely be frowned upon today, such as the protagonist hitting a woman, it's wrong, but the author seem to think that in the future it would be fine. But then, maybe there was a double meaning even in that?
The first story 'Mother Earth' by Isaac Asimov reminded me somewhat of the struggle against Nazism. The antagonists were all depicted as genetically superior, tall blonde characters, living on the outworlds. One of the earth men, playing a key role was depicted in a way that reminds me of a Jewish gentleman. Maybe I am reading too much into this shortest story. It was written in 1949, so the horrors of WWII would still be very real in his mind.
This was a good sample, I think, of what early Sci-Fi offered readers.