The perfect gift for an HIA practitioner?

You're in luck! There are three recent/soon to be published books that IAIA members have edited or contributed to:

Integrating Health Impact Assessment (HIA) with the Policy Process : Lessons and experiences from around the world - Monica O'Mullane

Health Impact Assessment: Past Achievement, Current Understanding, and Future Progress -John Kemm

Health Impact Assessment: Principles and Practice - Martin Birley

In the unlikely event that they don't want any of these Croakey has published a collection of health-related reading suggestions.