The first four Young Wizards books were published in paperback by Corgi/Transworld in the early 1990s. Their ISBNs:
So You Want To Be A Wizard — 0-552-52645-2
Deep Wizardry — 0-552-52646-0
High Wizardry — 0-552-52651-7
A Wizard Abroad — (ISBN to follow)
