It stands among the most famous theories ever created, but the general theory of relativity did not spring into being with a single, astonishing paper like the special theory of relativity in 1905. Instead, general relativity's birth was more chaotic, involving a handful of lectures, manuscripts, and more than one parent.
One hundred years ago this fall, that harrowing labor occupied almost an entire month in November 1915. When finished, Einstein finally delivered a theory perfectly formed, if not already mature, and trembling with potential. Today, the general theory retains its status as our modern theory of gravity, and its fundamental equations remain unchanged.
However, we've learned a great deal more about the back story and consequences of general relativity in the past century. In fact over time, this model of gravity, space, and time has come to be regarded by many who know it as perhaps the “most beautiful of all existing physical theories.” But to fully appreciate all the complexity of general relativity—in substance and creation—you need to start before the very beginning.