Lately, it seems that every book I pick up sparks an interest in more books. Every book.
For example, "Year of Wonders" has me looking for more books (preferably non-fiction) about the plague in Europe and China (since that's where it originated). I'm reading "The Gods in Winter", which has me re-interested in mythology. I'm still reading "Before the Fallout" (it's taking me forever, unfortunately), but now I want to read books about all the different scientists involved, including Michael Faraday, Marie Curie (and her family), etc, more books on the science involved, the aftermath in Hiroshima (I know what happened, but only barest of details) --which has now sparked in interest in learning more about Chernobyl, more about what happened to the Jews and other persecuted peoples during WWII, the camps, more about the Swedish government during WWII (which made the offer that any Dane seeking sanctuary could find it in Sweden), the Danish underground during that time (I've only read one book on that, "Number the Stars" and that was at least a decade ago), --which has sparked in interest in the French Resistance, --which has re-sparked an interest in the Underground Railroad here, which will lead me back to my childhood hero, Harriet Tubman...
I just finished a bunch of fantasy short story collections ("Farey Reel", "Firebirds", and "The Wolf at the Door"), which now have me searching for books by the various contributors (Tanith Lee, Neil Gaimen, Kelly Link...). Also, "The Wolf at the Door" was a collection of retold fairy tales, so now I want to look up them. Then there is the fact that since I've found two of Diana Preston book's so good, I need to get her other novels ("The Boxer Rebellion", "A First Rate Tragedy", and "Lusitania"), which will lead me to yet more topics.
No doubt, I could continue this for an hour...maybe making up some kind of flow chart. (Actually, that's not a bad idea. I'd be able to keep track of what sparks what, etc.)
But that's not the point, right? The point is...the point is that there are too many damn books. I will not be able to read every book that interest me, and I'll never be able to make even a dent in that "list" if I keep finding more interests.
I really wish I could blame somebody other than myself for this.
(edited: And I just finished two books over the weekend, which I shouldn't have done since it kept me up all night and has totally screwed me for sleep, which were about the Napoleonic Wars, but with dragons...and now I've got a whole 'nother set of interests.)