By first mention of something-or-other in the book

Here's where we open the book and start reading, searching for different types of key words. We have several options, naturally.

Chronologically, for example: by the first mention of a measurement of time that appears in the book. And there are many of those. Day, night, morning, evening, and more specific hours. Months and seasons, years or simply ”it was a long time ago”. I'd be curious to see if there are patterns – if certain genres or authors tend to begin their books at night, for example.

Another option is to search for the first name mentioned, and order alphabetically by them. Complicated by books with no names in them, but they are quite few, after all. One could also search for the first geographical name or word, or perhaps by the first colour mentioned. I'm sure imagination sets the only boundaries.