Excerpt from:  https://centennial.societyforscience.org/entry/1960s-the-science-program/

"In the 1960s and 1970s, Science Service partnered with Nelson-Doubleday to create a subscription service for youth called the Science Program. Subscribers received 64-page booklets on a range of science topics from space exploration to sound and hearing to crime detection. These books were another means Science Service used to expand science literacy and curiosity among youth."

No writing, marks, tears, folds or dogeared pages.