These 1964 sets of The World Book Encyclopedia are modest in value when you consider the number of volumes and the many that are in very good condition. Your sounds very complete and although there are a few Worldwide that have come up this complete this is a nice set. The Chicago published encyclopedia by Field Enterprises Educational Corp. currently has a rare book value in the range of 200.00-225.00 in good condition. It is not collectible, to answer your question, but none of the encyclopedias of the 20th century are highly sought after today..even the classics such as this one...just a reality.
I hope this helps.
Best wishes, Dori
PS Please remember to press "accept" as this is the only way JA pays its experts for their time and expertise! This button will not charge you further but credits me for my work.
PPS Positive feedback is very much appreciated. If you have any reason to leave "less than positive feedback," please contact me first, so that I can ensure that you are properly assisted with your question. I am happy to follow up and clarify or add further information.