The impact of software on society is both widespread and deep. It touches almost every aspect of our lives, from the way we bank and shop to the way we stay in touch with our friends and family. It helps us get our work done and entertain ourselves. It even affects the way we think and learn. It can even write the first sentences of a foreword. Yes, an AI wrote those sentences that you just read. But don’t be alarmed, I gave clear instructions to what it was supposed to say. Software is powerful indeed. But what is it made of, how is it made and how can it be so versatile?Consider the fact that the same programming language can be used to program a dish washer and a bank account. Even though the software in your dish washer and bank account are both machine code run by a processor, and the key words used to create the logic are identical, the rules that govern the two universes are distinct.Most people can tell the difference between a bank account and a dish washer, but from a programmers perspective there doesn't have to be one. For example, the dishwasher could connect to the electric company to check the spot price of electricity for the coming hours, decide to start when the price is low, and then make a transaction from your bank account to the electric company when it's time to start. It could also have paid your bills and made a recommendation to cut back on pasta and vanilla sauce by the time it's done.In this book I describe a philosophy. In a profession made of data every bit have been measured, recorded and analysed for the last 40 years. There is so much ground truth that it is hard to see the forrest for all the trees. I want the reader to see the forrest.