[javajosh]

I think you meant "recently published paper" but others are bringing up old stuff. I've always enjoyed Einstein's (translated) papers. They are both precise and readable, and his reputation for genius is well deserved!

This one is interesting, "On the Influence of Gravitation on the Propagation of Light" you can read here: https://einsteinpapers.press.princeton.edu/vol3-trans/393. This was his initial stab at GR. It was a simple approach, later abandoned, that considered light to slow down in a gravity well rather than remaining constant and specifying that mass warps spacetime. I suppose I like the idea that he pursued an idea that didn't work, and was forced to do something far more complex. It's kinda relatable.

[DennisP]

The book Einstein's Lost Key by German physicist Alexander Unzicker is all about that idea and its history. Unzicker argues that it's still a good idea, hasn't been falsified since it makes much the same predictions as GR, and we should look into it further.

[vackosar]

I read about criticism of General Relativity, that I haven't verified so grain of salt please. The criticism is in that the equations are so complex that only the simplest limits of them are studied and so the theory is therefore not verified.