Part I: Getting Started

You are about to write your first program.

That sentence might feel exciting, intimidating, or both. Either way, you are in the right place. Every professional software developer, every machine learning engineer, every person who has ever built anything with code started exactly where you are now: staring at a blank screen, wondering what happens when you type something and press Enter.

What This Part Covers

Part I lays the foundation for everything that follows. Across three chapters, you will go from knowing nothing about programming to writing real, working Python programs that take input, process data, and produce output.

Chapter 1 answers the question most introductory courses skip: What is computer science, actually? Not just coding, not just math, but a way of thinking about problems that applies far beyond the screen. You will learn the four pillars of computational thinking --- decomposition, pattern recognition, abstraction, and algorithm design --- and see how they show up in careers you might never have associated with "computer science."

Chapter 2 gets your hands dirty. You will install Python and VS Code, write your first program, run it, break it, and fix it. By the end of the chapter, the development environment that looked alien will start to feel like yours.

Chapter 3 introduces the building blocks: variables, data types, and expressions. This is where you learn how programs remember things, do math, and combine information. You will also encounter one of the first genuinely important ideas in computer science: that variables in Python are name tags, not boxes.

Why This Matters

Every complex program you will ever encounter --- from the app on your phone to the AI system that recommended this textbook --- is built from the same primitives you will learn in these three chapters. Values, names, expressions, input, output. The syntax is simple. The concepts are foundational. If you understand what happens when you write x = 42, you have the seed of everything that comes later.

What You Will Be Able to Do

By the end of Part I, you will be able to:

  • Explain what computer science is and why it matters in the age of AI
  • Install Python and a professional code editor on your own machine
  • Write programs that ask for input, perform calculations, and display results
  • Use variables of different types and format output with f-strings
  • Read simple Python code and predict what it will do before running it

How the Chapters Connect

These three chapters are a straight line. Chapter 1 gives you the why. Chapter 2 gives you the tools. Chapter 3 gives you the language. Each one builds directly on the last, and together they give you everything you need to start making decisions, repeating actions, and writing functions in Part II.

Your Progressive Project: TaskFlow

Throughout this textbook, you will build TaskFlow, a command-line task manager that starts simple and grows into a full-featured productivity tool. In Part I, you will meet TaskFlow (Chapter 1), create its first greeting --- "Hello, TaskFlow!" (Chapter 2), and give it the ability to store a single task with a timestamp (Chapter 3). It is not much yet. But every real application started as something not much.

The hardest part of learning to program is getting started. You are getting started right now.

Chapters in This Part