Elway was a scientist who lived before the mid-23rd century. This individual developed a theory on inter-dimensional travel that came to be known as the Elway Theorem.
Elway's theories were still taught to Starfleet Academy entrants in the 24th century. Wesley Crusher spent two hours learning about him in astral physics in 2365. (TNG: "The High Ground")
This character was only mentioned in dialogue.