This chapter expands on the use of the dictionary in the various mental health approaches discussed in the previous chapters. Many practice exercises in this sourcebook require the use of a dictionary. Therefore, it is important to proffer a rationale for this requirement, which is not yet based on sufficiently supported empirical evidence. Unfortunately, I have no data to support it, except for my clinical experience. Essentially, this proposal was the outcome of years of clinical work using programmed DW with individuals, couples, and families (L’Abate, 1986, 2008a, 2008b).