[Philip Lelyveld comment: this is a good overview article, but it leaves out the publicly traded 3D printer companies.]
It probably won’t come as a surprise to read that the term ’3D printing’ was coined at MIT. In 1995, grad students Tim Anderson and Jim Bredt hacked an inkjet printer to spew a binding solution onto powder to create 3D shapes. After a time, the experiments became a business and Bredt and Anderson founded Z Corporation which was acquired by 3D Systems in January this year.