Orthodontists have made remarkable progress in their understanding of physiology, growth, tissue response, increasingly sophisticated diagnostic techniques, available materials, and information. Nevertheless, with all these advances, many practitioners still find themselves at a total loss when confronted with that eternal dilemma: to intervene or not to intervene before the eruption of the complete permanent dentition. The objective of early treatment is to avoid or to simplify treatment of the permanent dentition. The therapeutic devices available for this endeavor are not complex, but deciding which ones to use and when to employ them is far from simple.