Humphrey Bancroft Neill

If you are new to investing and contrary thinking in general, it will be a very educational read. If you've already been around the block a time or two with these topics, it's still a worthwhile read, but nothing groundbreaking will likely come of it. Still applicable, but better books on the topic have been written since.

Think against the crowd.
First published in 1954 and still relevant.
Good read.

Humphrey Neill explores opposing or different views as a exercise in understanding a subject. He shows the tendency of the dominant opinion to attract followers who underweight of even ignore dissonant information, hence leaving themselves open to a "reality shock".
An example from this interesting book is the world's disbelief in 1914 as Germany declared war on Russia and invaded Belgium and France.