I bought this set of "encyclopedias" while I was in High School. I wanted to study Oceanography in College as I was, and am still mesmerized about the Ocean. Took another career, Water Treatment, as the school was far more than I could afford. So, didn't become an Oceanographer, scuba dived in the Ocean for fifteen years, and treated raw water for thirty years for the public to drink. Now finally to read the 20 Volume set that was published in 1973.