When I did a Dewey Decimal analysis of my writing using that AI
   at [1]http://act-dl.base-search.net/textclassifier - then
   weighed for frequency and its own confidence level, 115 TIME was
   my first and 120 Epistemology, causation and humankind was my
   second, with 122 Causation as my third.

   I suspect we're all speaking in the same field. Alas, there are
   not too many books specifically any of those subjects.

References

   Visible links
   1. http://act-dl.base-search.net/textclassifier