[ninty]

Einstien presented many theories, so yes there are theories that people will question, and that's what science is! Put fourth a theory and other scientists test it. If they come to the same conclusion, then the theory is correct, if not, the theory might be wrong. Many of Einsteins theories are accepted as being correct. Einsten even hypothesized at dark matter, and just now we are seeing the evidence that it does exist.
I've read Einsteins "Relativity", and I would like to get into some of his essays as well.

But there were some things even Einstein couldn't solve. The theory of everything. Einstein tried to merge the theories of gravity and electromagnetism with the strong and weak nuclear forces. Once we can do this it will give us a theory of everything. An equation that can explain quantum physics as well as the cosmos. He couldn't figure it out. And we still can't today. Many people look to string theory, but I think thats got a ways to go yet. Hopefully someday we can have a theory of everything.