Checking up on Five for Silver at Amazon.com I was startled to see, below the title listing and the first sentence of the book (which is actually not the first sentence of the book, which has a prologue, but of Chapter One) a notation -- SIPs: oral will.

Amazon.com tells me this is a Statistically Improbable Phrase

Amazon.com's Statistically Improbable Phrases, or "SIPs", show you the interesting, distinctive, or unlikely phrases that occur in the text of books in Search Inside the Book. Our computers scan the text of all books in the Search Inside program. If they find a phrase that occurs a large number of times in a particular book relative to how many times it occurs across all Search Inside books, that phrase is a SIP in that book.

Once we identify a phrase that is statistically improbable:

For books where the phrase is a SIP, we provide an exact count of and link to the occurrences in those books.

For books where the phrase merely appears in the book, we provide a link to those occurrences

The SIP is revealing. Much of Five For Silver hinges on an oral will. Which is why the phrase occurs 13 times. However, our detective, John, doesn't figure this out for awhile. Internet access would have saved him a lot of traipsing around Constantinople.

I have to wonder whether SIPs might prove to be spoilers for certain mysteries? (Why does "alabaster vial occur 22 times in Stephen Saylor's The Judgment of Caesar?) Or reveal the authors' clumsy handling of clues? A book isn't real life, after all, only a (cunning?) arrangment words. Maybe it would be easier to finger the culprit in a mystery novel by a computerized structural analysis.