In the first few chapters, the goal was to gain familiarity with handling models and building them. This time we've looked at preparing a model for texturing. In the next chapter, we look at texturing using the same content. You will probably have noticed that modeling is an involved process, and so is UV mapping. Also it should be no surprise that so is texturing, and the amount of time for each can grow, stage to stage, if you are really shooting for high quality.
Actually, UV mapping is not difficult, but there is a lot of repetition and you have to be willing to handle the puzzle of UV packing with a light heart and think of it as a game. It's not much fun to try it under intense deadline pressure, for example, though increasingly there is a move towards automation along the lines of PTex or UV-Packer. For instance, both Mudbox and ZBrush include UV mapper tools that can do a lot of this work for you. At the end of the day, as a modeler you should appreciate how UV mapping works...