On page 42 you write
recur binds new values for loop’s bindings and returns control to the top of the
loop.
I recommend to add, that recur must be invoked in a tail-recursive position, this is what I asked myself while reading these lines. Such a comment would be enough for me, but in addition you could also explain what “tail-recursion” means, e.g. by giving a couter example such as
(defn fac [n]
(if (<= n 1)
1
(* n (recur (dec n)))))
which leads to the error message Can only recur from tail position.