We are grateful especially to Josef Cibulka and Jan Kyncl for providing 
us with a list of errata in this second printing. Here are some of the
more serious problems. (Most of these are also present in the first
printing.)

Page 27, proof of Lemma 1.36: Any two vertices can be joined by an
oriented walk (not path) x_1, x_2, ...

Page 74, Proof of Proposition 2.70: The sequence f(s_1), f(s_2), ... 
(not f(s_1), f(s_1),...)

Page 78, Exercise 7 in Section 2.14: G.H has edges (u,v)(u',v') as 
defined, but with u and u' distinct.

Page 88, last line of the proof of Theorem 3.12: This is easily enforced
by choosing \ell greater than the odd girth (not girth) of both G and H.

Page 94, Theorem 3.24: The random graph G(n,1/2)...,  AND