1973. Varied conditions. Most not opened all the way. Definite spine cracks and exposed to water at some point. These were library books at one point. I’ve owned them for over 10 years and they have never been treated poorly in my possession, so they are in the same condition as when I received them. Volumes 1-4, 6-10, 14, 15. (Condition noted.) 1 Transportation 7/10 2 Animals 6/10 3 (No name, but it’s Plants) 5/10 4 Inventions 6/10 5 Birds, Fish, and Insects 7/10 7 Exploration and Discovery 6/10 8 Treasures of the Earth 7/10 9 Sciences and Technology 6/10 10 Myths and Legends 5/10 14 Stories 8/10 15 The Human Body 8/10 I will sell separately for $8/each or $55 for all, pre-ship price.