From publisher blurb:
Energy dragons represent the apex of the environments where they dwell. Each dragon particularly favors a specific element or energy type, creating lairs that are overflowing with that element. Energy dragons are typically selfish and have deeply conceited plans that can take many years to come to fruition. Each dragon has colorful scales that typically reflect the environment they inhabit or represent the effects of their elements on their body over a long period of time.
This supplement provides: 8 new dragon families ranging from juvenile to fabled versions of their statblocks, spellcaster template for each family, and a new wyrmling form spell for you to shape into a less powerful dragon at lower levels before you gain the dragon form spell!