Your next/previous letter of recommendation ?
"You write to ask me for my opinion of X, who has applied for a position
in your department. I cannot recommend him too highly nor say enough
good things about him. There is no other student of mine with whom
I can adequately compare him. His thesis is the sort of work you
don't expect to see nowadays and in it he has clearly demonstrated his
complete capabilities. The amount of material he knows will surprise you.
You will indeed be fortunate if you can get him to work for you."