As an art and a craft, it requires the artistic skill to conceive an appropriate and workable design with consideration for the breaking tolerances of glass and the engineering skills to assemble many pieces of glass into one fabulous work of art!
On the other hand, Stained Glass Art follows a set of procedures that anyone can learn.
Working with stained glass requires training and guidance from experienced professionals. To produce a stained glass window, each individual piece of glass must be cut from a pattern (called cartoon) as close as possible to the edges. Since the glass is not going to break exactly along the edges of the pattern pieces, each one will need to be grinded down to fit the pattern precisely so that when they are assembled they will fit together perfectly without spaces in between and able to fit into the original planned framework.
And that's just a very brief explanation. The process of creating with stained glass has many steps and can be a physical journey but with training and the understanding of glass you will be most rewarded.
"Stained glass" refers to both the colored glass material and to the works of art produced from it. For most of its thousand year history, stained glass has referred to the windows of churches and other buildings because traditionally it has been assembled in flat panels and used as windows.