Kent Beck might deny that Kent Beck needs an entry in the programmers' library. "All I did was rediscover what other people had done before," he might say, or "all I did was to interpret what Ward Cunningham was doing." But that discovery, that reinterpretation, is the most important part of the process. One person doing things differently is an oddball. Two are the beginning of a revolution.

Here are some hard questions. If you were to write a book about any subject related to computers, which programming language would you choose? If you had to teach programming to an absolute beginner, which one would you choose? If you had to explain some algorithm that could be implemented in any Turing-complete language, which one would you pick, and why? These questions are not easy, nor they are new.

Let's start at the end. The last sentence in "NeXTSTEP Programming Step One: Object-Oriented Applications" by Simson L. Garfinkel and Michael K. Mahoney looks like this: "Go out and write a killer app!" This is slightly punchier than the way the same authors signed off in "Building Cocoa Applications: A Step-by-Step Guide": "Now go out and write a killer application!"

Of all the articles I have written in this “Library” section, this has been by far the most difficult to write of them all. It is extremely hard to summarize in a thousand words the major achievements of a person that has defined the way our modern world and our industry work, in the most unfathomable ways. Because, to be honest, it is hard to find a starting place when talking about those who have such long resumés as Mr. Kernighan. Let us try to find some starting points and see where this takes us. Let us pick one major milestone: this is the person who gave UNIX its name.…