We considered a variety of problems in Chaps. 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , and 10 that fall within the domain of either biosolid mechanics or biofluid mechanics, each of which is important in its own right. Yet, whether in the body (in vivo), in a bioreactor (ex vivo), or in the laboratory (in vitro), many “real-life” problems simultaneously involve solids, fluids, and their interactions. For example, although we may seek to determine stresses in the limbs of a pilot who has ejected from an aircraft for purposes of identifying safety measures, it is the airflow that induces the applied loads of importance; most intracranial aneurysms may be considered as thin-walled, nearly spherical membranes that exhibit a solid-like character, but the applied loads are due to the internal flowing blood and the surrounding cerebrospinal fluid; mechanotransduction in bone, which exhibits a strong solid-like behavior, is influenced directly by loads due to weight bearing as well as those due to the flow of blood and bone fluid within the many different canals within the bone; and an atomic force microscopic examination of the mechanics of a cell may primarily reveal the properties of the cortical membrane and underlying solid-like cytoskeleton, but flow of the cytosol can play a key role as well, particularly when measuring viscoelastic behaviors. Hence, from these simple examples, and many more like them, we see that solid–fluid interactions are important at the organism, organ, tissue, cellular, and molecular levels. Indeed, although it tends to be convenient to introduce students to a field by focusing on one subject, most basic science, bioengineering, and clinical problems require multidisciplinary approaches, that is, solution of coupled problems in analysis and design. Such problems are typically complex and require advanced approaches, but here we consider a few introductory examples.