This is a long long looooong text (900 page PDF) but so good. It takes its time, explains clearly, and stays well within a traditional perspective, which is what we want from a textbook. Thus we read to the end of page 68 before we have finished defining philosophy as "the personal search for truth, in any ﬁeld, by rational means." We then have another 95 pages defining 'computer science' (including some side-discussion on whether we should be drawing sharp boundaries in general, and a detailed consideration of whether computer science is a type of magic). Do look at the five key insights (pp148-149). So what is computer science? Essentially, "to capture the messy complexity of the natural world and express it algorithmically." That sets up the next question, "what is science," and so on. I don't think you could ask for more from such a text, really, not even brevity. Image: XKCD, also on p. 318.