The oldest book I've been able to find on spool knitting is Spool Knitting by Mary McCormack, copyright 1909 by A. S. Barnes & Company and published by Beckley-Cardy Company in Chicago. I purchased my copy on e-bay several (4-5) years ago.
I saw one for sale and bid on it but dropped out when it reached 20 dollars (it went for about $26). I kicked myself later. I would, I reasoned, have paid $25-30 for a new book surely I could have gone that high for a collectible book. A few months later another copy came up and I bid it up to $50 before I dropped out. And again, I thought about it and kicked myself. After all, what treasure trove of information might be in it? So when, a couple of months later a third copy went up for bid I set a whopping $80 as my limit and bid away. It went for over $100- to someone who wasn't me. About a year after I saw the first copy on e-bay a fourth copy was put up for auction. I threw all good sense to the wind and bid on it. This one was going to be mine at any cost. I got it for about $24 (including shipping). I guess all the other crazies already had theirs.
I went googling to see what I could find out about the author and found that the book is now available for free on Project Gutenberg.