The book is primarily focused on the kind of data science done by operational and product-focused data scientists, less so on engineering and research. What a data scientist does and what skills they need depend on the data maturity of their organization. Unless data science itself is the product, its end goal is to change opinions. A data scientist is only as good as their understanding of the data. It is also important to know where data comes from and why it was collected in the first place. Things get complicated even before you start analyzing data. There is no such thing as “raw” data—data is never given and is always the results of someone’s observation and measurement.