You are looking at a very gently handled vintage 1946 edition of Volume 13 (S) from the 

COMPTON'S PICTURED ENCYCLOPEDIA and Fact-Index

This simulated leather cloth-bound hardcover volume features black cover with the front embossed; green bars with gold lettering on the spine.  Excellent condition; binding solid; covers and all pages intact and in very good condition with very little wear.  Great volume for adding to or completing your set and a great stand-alone volume.