The dlib installation fails with the error "cmake configuration failed!"

Question

When I try to install dlib using pip install dlib, it fails with this error:

CMake Warning at /usr/local/lib/python2.7/site-packages/\
    cmake/data/share/cmake-3.8/Modules/FindBoost.cmake:765 (message):
            error: cmake configuration failed!

Command "/usr/local/bin/python -u -c "<stripped for brevity>" \
    install --record /tmp/pip-nSRKWl-record/install-record.txt \
    --single-version-externally-managed --compile" 
    failed with error code 1 in /tmp/pip-build-nJyga7/dlib/

What could be the problem?