I have to marvel at the success of the For Dummies series. People just love these books. It shows you how intimidating books and reading can be. Knowing that this series exists has actually given people a comfortable way of asking for a book on a topic they know nothing about. They will ask, "Do you have something like a (Subject) for Dummies?". A rival series, the Idiot's Guides, has not done nearly as well. I remember a similar effort, years ago, the For the Millions books.
Today I had a man ask for a beginner's book on Windows. I asked what version of Windows he was using, and he said XP. "This has all passed me by", he said, "it's time to catch up." After showing him some of the "easy reader" books on PC's for seniors, I decided he could handle stronger stuff, so we looked at the XP books. We had a Peter Norton title, a Sam's title, a title in the Missing Manual series. We do actually own Windows XP for Dummies, but it was, of course, checked out.
I spotted Teach Yourself VISUALLY Windows XP, one of a series that teaches using color screenshots. I handed it to him, saying, "This is the closest thing we have on the shelf to an XP for Dummies book". And that closed the sale.