I noted your indirect response via cat-net. Here are some more for your checking that I noticed since my first message: Errors in TTT Book - 1. Page 53, diagram (7): the vertical arrows should be pointing upward. 2. Page 54, lines 5-6 from the bottom: "... definition of universal arrow ..." - well, this definition does not appear explicitly in Section 1.5 as suggested. It certainly arises from Lemma 3 on page 28, but no hint is given there as to that lemma's translation into universal arrows. 3. Page 55, line 4: the typing of the psi-A weak universal arrow should be "A -> RWA." in order to be consistent with the discussion at that point. 4. Page 55, line 14: "The arrows Ry ..." should be "The arrows y ...". 5. Page 64: the diagram at the bottom should be labeled "(1)". - Dwight Spencer Dept. of Computer Science and Engineering Oregon Graduate Institute