It's also a classic, I used it as text in a course back in '98 or so. Also it's more widely used outside of USA, personally I believe that is because it is inex

It's also a classic, I used it as text in a course back in '98 or so. Also it's more widely used outside of USA, personally I believe that is because it is inexpensively reprinted and because Feller was Croatian. I believe it has been translated to a number of languages including Chinese and notably Japanese.