I'm trying to build libRocket, but I can't get it to build the Python bindings. CMake can't find Boost, apparently:

Variable Name: Boost_DIR
Description: The directory containing a CMake configuration file for Boost.
Current Value: Boost_DIR-NOTFOUND
From Synaptic I've installed every boost-related package I can find, but nothing seems to help

(from what I've read I expected libboost-all-dev and libboost-program-options to do the trick, but so far no joy)

Is there something else I should install? Where is the Boost Directory supposed to be?