I came up with “Moore’s Law of Literature” about a year ago.

It is quite simple, and so far, always accurate.

Here’s how it works.  I take the total number of pages a book has, so in the case of The Last Days of Socrates by Plato, we have 183.  I divide this by 2 so 91.5.  If the total of my marginal notes exceeds 91.5 then it is a formative book.  In the case of The Last Days of Socrates I made 102 marginal notes. 

Fortunately, even the modern books I’ve read this past year have all passed the test.  If I went back over a lifetime of reading there would be many books that would not.