Bachra takes a fresh look at the issue of phonotactic constraints in the consonantal verbal roots of the Semitic languages. This topic has received much previous attention, both descriptive and theoretical. The prevailing view is that consonant combinations in verbal roots are avoided when those consonants share major place of articulation features. For example, roots in Arabic containing both /b/ and /f/ are highly underrepresented, and these two consonants share [labial] place. In generative analyses, this constraint is considered to be an instantiation of the Obligatory Contour Principle (OCP), restricted to place of articulation features (e.g. McCarthy 1994). There are, of course, some complications. The constraint is partially sensitive to manner features, as combinations of coronal obstruents and coronal sonorants are permitted. In addition, the set of uvular, pharyngeal and laryngeal consonants is prohibited from co-occurring, indicating that shared place of articulation can be construed rather broadly. Finally, the constraint is gradient, rather than absolute. In many cases, consonant combinations that share place are found, but are just very infrequent.