I was given a 5th and 15th editions by a co-worker that belong to his grandfather about 15 years ago. The first new one I bought on my own was the 20th edition. That was 41 years ago, I was still in high school then. Borrowed a 23rd edition from a company library that has about 30 of them left over from a training seminar they had. Last one I bought was the 26th edition, but I bought the large print edition along with the CD. And no, I will not provide any copies of the CD to anyone! Go buy your own like I did. Haven't decided if I will buy a 30th edition or not.