Instruct: Classify Amazon reviews into positive or negative sentiment
Query: nonstop 'adventure' sinks into boredom...

I'm a sucker for vintage SF. The Planet Stories series of books looked very interesting, and as a first I bought this book based on the glowing reviews here on Amazon. This book might have been ok decades ago for readers who never read any of the better SF/fantasy works before encountering this one. But unlike many classic vintage SF, this book just doesn't measure up today. The book contains a huge number of 'adventures', but around halfway in the book, after the 357th miraculous escape/victory I just didn't care any more. There was no tension or excitement. The characters are not likeable or interesting either, so I wasn't rooting for them. Overall the book was a big letdown, and I'm afraid that if this book reflects the average quality of the Planet Stories series, then this was the last one I bought.