Er, speaking as a physicist.... relativity is nothing to do with the world being random or anything like that. It's a very deterministic theory, indeed its originator (one A. Einstein) had doubts about the Heisenberg Uncertainty Principle until the end of his days. The HUP is the one that in a manner of speaking says it's all random, but only up to a point.
Special Relativity is a very simple theory that conveniently (and correctly, as has been experimentally verified in the century or so since its formulation) explains how the speed of light is constant to all observers everywhere. Most teenage science majors understand it fairly well, at least mathematically.
General Relativity is a rather complicated theory explaining stuff like how light is affected by gravitational fields. Only real propellorheads understand it in any very meaningful sense.
And by the way, for whoever was asking, the York Bowen Preludes have been out of print for many years. I've got a copy and might just about be persuaded to copy them one of these years....