Non-fiction:
The Travels of Marco Polo - I read this as a kid, now I'm re-reading it and finding it even far more fascinating than the first time I read it. I've got an old copy version translated from the Italian but still preserving many of the original terms. I also got an unabridged copy of the book on tape and have been listening to that. Polo was a brilliant explorer and gets far too little credit for his actual achievements and observations.
The Codex of Archimedes - I started reading this because of the work of translation regarding the Palimpsest. But to my great amazement and enjoyment it had extracts from the newly discovered Method sections and it had an analysis of some of Archimedes's methods for measuring infinity as a geometric principle. This gave me an idea for one of my own equations. I've been working on a mathematical formula for the resolution of infinity for about ten years now. When I read of what Archimedes was doing it suddenly struck me that I could achieve a result by approaching the problem as a geometric, rather than a theoretical one. Then I was able to finish my equation. Or one of them, because my original equation has led to suspect that there are three different types of infinity. Once I run the equation through numerous tests and try and examine the intermix of every variable to my satisfaction then I'll seek to publish it. I'm also gonna write the equation in a simple, ordinary language version, and in a more standardized, mathematically symbolic version. But this book was extremely helpful as the inspiration for helping me look at the problem in a very different light. I highly recommend it.
The Survivors Club - A very useful book about human factors in survival situations. I found the equation on "luck" {λ(E) = ∆(E) x [1-pr(E)] = ∆(E) x pr(not-E)} to be a fascinating way of looking at good fortune not as a matter of chance, but as a matter of risk. It even gave me some ideas about "Fortune" as both a matter of "enterprise-risk" and as one of "game and/or speculated-risk"
Fiction
I just finished the Dresden novel Dead Beat and now I'm reading Turn Coat. I like both books but I think I'm liking Turn Coat so much because of the situation where Dresden is secretly investigating the Council (something he should have done long ago) and because of the situation with Morgan.
Black Hand - This excellent little detective novel speculates on the Mafia operating in Victorian London rather than in Sicily or America. It is quite good and reminds me a lot of Arthur Conan Doyle, but more informal and looser in style, especially narrative style and point of view.
The Daughter of Time - This is a really interesting book I'm listening to on CD about a Scotland Yard dick who is up in the hospital. To keep himself from getting bored during his recovery he examines portraits of people and decides to investigate the case involving Richard the III. It is written in a really wordy, snooty sort of English style, but the story and detective work are pretty fascinating. I'm not very far into it yet but it is very good. It will be interesting to see what conclusions the main character draws about who killed the Princes, assuming of course they were killed.
Soon, with my daughters (as part of their homeschooling) I'm gonna start re-reading the Great Books of the Western World, but this time from beginning to end. One book a month or so. That will be part of my non-fiction studies, and part of their general education.