The Book of Popular Science, published by Grolier Society (HC, 10 volume set, 1974, $10, which is 1/3 the internet price)
"Science means knowledge; the sciences represent the sum total of human knowledge in their particular fields. In the 15 groups, or departments, of which THE BOOK OF POPULAR SCIENCE consists, the reader will learn about the major sciences and about their applications in the world."
Essentially this is a science encyclopedia.If you want to read what scientists thought in 1974, this is the set for you. Look for it on the floor of the science section.