Adolescents with Anxiety

For adolescents with anxiety I would suggest
Fighting Invisible Tigers, by Earl Hipp:

or  Too Stressed to Think by Annie Fox and Ruth Kirschner:

or My Anxious Mind:  A Teen's Guide to Managing Anxiety and Panic, by Michael Tompkins and Katherine Martinez:

All of these books are great to develop cognitive-behavioural strategies and to learn more about symptoms.