Insomnia is an international public health problem associated with functional impairment as well as significant social and economic burdens (Daley et al., 2009; Matteson-Rusby et al., 2010). In the past, clinicians treating patients with PTSD held the same view that many sleep specialists had. That is, if difficulty initiating and maintaining sleep seemed to be caused by another problem (e.g., PTSD), then the other problem should be treated first. In fact, the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (American Psychiatric Association, 2000) contained a diagnosis called “secondary insomnia” to describe this situation. However, research has consistently shown that treatment can improve insomnia symptoms even when the conditions that seem to “cause” the insomnia are still present.