Absolutely. But one must take apart the introverted paradigm/stigma of what we're talking about within this question first, which can be done - in short - by looking at: What was 'normal' for the author (assuming that we're talking about good literature) of great books?
And this inevitably was to cross-pollinate different disciplines into one. All of the best wrriters have done this by living a varied life.
So the question of whether it is normal or not should be reflected upon with how the subject matter in question is created. And this in short, is from a blend of facets of life; so yes, it's normal to want to live inside books, but even more so if the reader appreciates the variety of life constituting the amalgamation of the passion that they're enjoying, and perhaps, more importantly, does the same themselves.