More than just a spy novel,
LeCarre's book's have claims to serious literature, not just spy novels, and I think this is one of his best. LeCarre, like all great novelists, is good at characterization, and a great observer of people.
Which brings me to my main point. You don't ever want LeCarre describing your face. He is always noticing odd things about people's faces, especially the moisture on a person's face. I noted this several times before. He'll make you sound like a greasy second-story man no matter what you look like, it seems.
My point notwithstanding, LeCarre is a great novelist.