"tail recursion" SICP problem

Hello.

I read SICP and I find it hard to understand the "tail recursion". He says the book, which is a function of "tail recursion"as he calls himself, and not the other functions. But she does not "tail recursion":

(define (f n)
           (if (= n 0)
             1
             (* n (f (- n 1)))))

This is the "else branch"is called. What's up?

(To my English, forgive me am German makes happily speaks, because I, and to the English.)

This english is trolling. No German would make english mistakes in this way.