Foreword When the publisher first sent me a draft of this book,I was immediately excited. Disguised as a Python textbook,it is really an introduction to the fine art of programming,using Python merely as the preferred medium for beginners.This is how I have always imagined Python would be most useful in education:not as the only language,but as a first language,just as in art one might start learning to draw using a pencil rather than trying to paint in oil right away. The author mentions in his preface that Python is near-ideal as a first pro- gramming language,without being a"toy language."As the creator of Python I don't want to take full credit for this:Python was derived from ABC,a language designed to teach programming in the early 1980s by Lambert Meertens,Leo Geurts,and others at CWI (National Research Institute for Mathematics and Computer Science)in Amsterdam.If I added anything to their work,it was making Python into a non-toy language,with a broad user base and an exten- sive collection of standard and third-party application modules. I have no formal teaching experience,so I may not be qualified to judge its educational effectiveness.Still,as a programmer with nearly 30 years experi- ence,reading through the chapters I am continuously delighted by the book's clear explanations of difficult concepts.I also like the many good excercises and questions which both test understanding and encourage thinking about deeper issues. Reader of this book,congratulations!You will be well rewarded for studying Python.I promise you'll have fun along the way,and I hope you won't forget your first language once you have become a proficient software developer. -Guido van Rossum ixForeword When the pubHsher first sent me a draft of this book, I was immediately excited. Disguised as a Python textbook, it is really an introduction to the fine art of programming, using Python merely as the preferred medium for beginners. This is how I have always imagined Python would be most useful in education: not as the only language, but as a first language, just as in art one might start learning to draw using a pencil rather than trying to paint in oil right away. The author mentions in his preface that Python is near-ideal as a first pro￾gramming language, without being a "toy language." As the creator of Python I don't want to take full credit for this: Python was derived from ABC, a language designed to teach programming in the early 1980s by Lambert Meertens, Leo Geurts, and others at CWI (National Research Institute for Mathematics and Computer Science) in Amsterdam. If I added anything to their work, it was making Python into a non-toy language, with a broad user base and an exten￾sive collection of standard and third-party application modules. I have no formal teaching experience, so I may not be qualified to judge its educational effectiveness. Still, as a programmer with nearly 30 years experi￾ence, reading through the chapters I am continuously delighted by the book's clear explanations of difficult concepts. I also like the many good excercises and questions which both test understanding and encourage thinking about deeper issues. Reader of this book, congratulations! You will be well rewarded for studying Python. I promise you'll have fun along the way, and I hope you won't forget your first language once you have become a proficient software developer. —Guido van Rossum IX