Bowman Books
I really enjoyed talking to Mr. Sidney (S. D.) Bowman. I talked to him when I was writing "Pipe Fitter's Math Guide." then later as we began to sell other pipefitting books including his three books. He died many years ago now but he was a key to the past in this type of work. His books cover how to do the really difficult fits you might run into out there. I kept his books in mind as I wrote my math book. I wanted to take people to a place where they could start his and do the hard stuff. I asked him once if the people he wrote for were prepared to start his book and he said yes because he wrote in a different era. The craftsmen of his era started apprenticeships before the GI Bill diverted a lot of people toward 4 year degrees. They had the smarts but not the money to go to universities so they got a trade.