Who were the muckrakers and what did they do?

The Muckrakers were a group of journalists, who would 'rake up the muck' of the slums of america, or other areas, and try to expose it. An example of a muckraker is "The Jungle" by Upton Sinclair Jr, where the meat packaging industry is revealed to be extremely unsanitary and lurid.

If this is a true or false question i would say true