In my first book in this series, "Build Your Own Computer-From Scratch", I started with a few basic concepts and guided the nontechnical reader through the design of a working computer. The emphasis was on hardware design with less attention paid to software. In this book, software is the focus. As before, I make no assumptions regarding your technical knowledge of computers. I start with a few basic concepts and build a version of the BASIC programming language. To test Tiny BASIC, we use the BYOC-24 CPU, a modified version of the computer design introduced in my first book. We first test Tiny BASIC on a simulated BYOC-24 CPU using the freeware application Logisim. Later, we make Tiny BASIC fully functional using an Intel Cyclone V field programmable gate array. Given this brief introduction to computer language design, I believe you will be encouraged to explore other areas of computing. At the very least, I hope you will appreciate more fully what happens when you type "RUN", "COMPILE", or press the green "GO" button in whatever computer language you use.