A few small encores on auction theory, and then--how can you value a piece of information before you know what it is? Decision theory has some pointers. Some highly relevant information if you are trying to figure out how much to pay a spy.
Relevant links:
https://tuecontheoryofnetworks.wordpress.com/2013/02/25/the-origin-of-the-dutch-auction/
http://www.nowozin.net/sebastian/blog/the-fair-price-to-pay-a-spy-an-introduction-to-the-value-of-information.html