1979 grade A+
2019 grade B+
A 1969 book about investigating para-psychological ability in people. The prose ranges from riveting, to ordinary, to long boring paragraphs. Fortunately, most of it is in the fist two categories. Still, it is pretty old.
The story contains a great real world component which does have a very good concrete conclusion. The para-psychological side does not end quite as clearly but is good enough. I can't really recommend the book but it is good and worth a read, if you can find a copy.