Here is a very nice biography, summary and tribute. I chatted with Mark many times and always considered him a true scholar and gentleman. I grew up learning from all of his books and as a kid read his Economic Theory in Retrospect several times (it’s actually the book I learned neoclassical economics from), plus his book on Ricardian Economics and his pamphlet on the Cambridge Capital debates, as well as many many other contributions, including extensive writings on the economics of education and economic method. He was one of the best informed and wisest economists and I was very sorry to hear of this loss.
For the pointer I thank DG.