It's a fun new craft that's only been around since the 1980s.  I like to describe needle felting as sculpting by stabbing using wool as the medium and special needles with barbs on the blade as your tool.    Felt is created as the barbs of the needle tangle and compact the fiber with repeated jabs.  My specialty is sculptural or 3d needle felting but the same principles apply to 2d or flat needle felting as well.  In contrast to traditional felt making methods that use water and friction, needle felting is also known as dry felting.   Felting needles are borrowed from commercial felting machines used in the non-woven textile industry and have been adapted for handcrafting use.    

Thanks for watching and have fun!