How can I build strong computer science fundamentals from first principles?

Use structured material instead of relying only on experimentation. Books such as *But How Do It Know?* and *Code* explain the path from simple circuits to computer hardware and software, while the NAND2Tetris course lets you build a computer system layer by layer. Assembly and networking are also useful areas to study. Take your time—the basic ideas are manageable individually, but there’s a lot to absorb when you first connect them.

Choose a concrete area or goal rather than trying to learn all of computer science at once. Depending on what you want to do, you could build a small database, message queue, rendering engine, user-interface library, robot, or SLAM system. A specific project gives you a reason to learn the relevant concepts and makes it clearer which fundamentals actually matter.

Practice observing how systems behave, then form an explanation for what you’re seeing and test it. Combining that habit with a structured curriculum and projects is usually more effective than either reading or building alone. It also helps to define a goal first, since the fundamentals needed for a systems programmer, application developer, or infrastructure engineer will overlap but aren’t identical.

Get a basic model of how computers operate: registers, memory, CPUs, caches, and the layers between hardware and software. Studying computing history also helps explain why certain designs exist and why particular ideas appeared when they did. You don’t always need to understand an entire system from first principles—working through one component or mechanism deeply is valuable too.

Start by building things and paying close attention to their behavior. It can even be useful to deliberately try an approach that isn’t recommended, then observe how complexity and design problems emerge. That hands-on experience makes the reasons behind established practices much easier to understand.