Dr. Timothy Root is awesome! He's super informative, has a pleasant demeanor, and is just plain hilarious.
Also, he knows how to perfectly pitch his lectures to his audience. At least in my experience I've seldom found intelligent and knowledgeable people are also great teachers and communicators. But Dr. Root certainly is all of the above.
I highly recommend his website which features his book as well. It's excellent for the med student. Although probably too basic for an ophthalmology resident.
Best of all? Everything on his website appears to be free as in free beer (gratis).
And, no, I don't know him or get paid by him or have any other sort of affiliation with him. I just appreciate his work!
