Foreword

There’s a wonderful scene in the movie 2001: A Space Odyssey that comes to mind.

Having spent several months alone on the derelict ship Discovery—and that after having earlier lobotomized the errant Hal—Dr. David Bowman approaches a monolith that draws him in to a new world. His final message back to earth ends “It’s full of stars!”

Software-intensive systems are new worlds that we create with our own mental labor. Whereas the world that Bowman saw was formed from atoms and thus full of stars, our worlds are formed from bits...and are full of patterns.

Whether intentional or not, all well-structured, software-intensive systems are full of patterns. Identifying the patterns in a system serves to raise the level of abstraction in reasoning about that system; imposing patterns on a system serves to bring even further order, elegance, and simplicity to that system. In my experience, patterns are one of the most important developments in software engineering in the past two decades.