On a third occasion, I wrote only the introduction to the column, stepping aside for the distinguished Danish computer scientist Bjorn Stavtrup. That's a lot of stuff to be scattered in periodicals all over the place. If the articles are useful individually, they should be evenmore useful when collected. The first reason is that I think you'll enjoy it. They are curriculum-based.
Enjoyment is secondary at best.
Magazine columns are different. I suppose there must be some people out there who thumb through a copy of JOOP in a bookstore and skim my column before deciding whether to buy the magazine, but it would be arrogant to think that there are more than a few. Most readers will be seeing my column after they've already paid for it, which means that they have a completely free choice about whether to read it or not. So each column has to be worth reading on its own. This book contains no long, boring discussions of obscure details.