  Cooling of hadron beams (including heavy-ions) is a powerful technique by
which accelerator facilities around the world achieve the necessary beam
brightness for their physics research. In this paper, we will give an overview
of the latest developments in hadron beam cooling, for which high energy
electron cooling at Fermilab's Recycler ring and bunched beam stochastic
cooling at Brookhaven National Laboratory's RHIC facility represent two recent
major accomplishments. Novel ideas in the field will also be introduced.
