Earlier this year I read "The Russia House". First, I will say that I did not like the movie, which I saw when it came out years ago. That may have colored my enjoyment of the book? The plot seemed "routine" and not very interesting.
More recently, I finally got around to reading the classic, epic "The Spy Who Came in from the Cold", published in the early 1960's. I can't tell you what a block-buster novel that was! This was the book that introduces the best "little grey man" master spy character ever, George Smiley, in a supporting but vital role. (I love the character. George Smiley. He's not.) The writing is pure and clean and tightly edited. It is not a "feel good" cozy book; but any tangled, confused emotion you have as you read seems perfectly intended!
With "Russia House", if I were a skeptic (and I am) I'd suppose it was written to inspire a screen play to employ Sean Connery one more time.