This series is supposed to have 12 books, but unfortunently, I only have 10. I may still be able to get the other two this weekend, if you want to wait and see. Anyways, this series, from 1953, is the fourth edition. There is so much information in these books about everyhing electricity, including insulators! Also, railroad signals, and lots of other stuff. There are 5,691 pages in these ten books, even more with the other two. Right now, with it missing two books, the price is $35 plus shipping by book rate, not more than $12. If I get the other two books, the set will go up to $40 plus shipping, not more that $15. I suggest you hold off on buying, and sleep on it, wait and see if I get the others. If I can't get the others, I'll lower the price. Insulator Trades accpeted. Shipping can be combined, and other methods of shipping are optional. Let me know.