The cells of our bodies represent a very large class of systems whose structural components often are both complex and soft. A system may be complex in the sense that it may comprise several components having quite different mechanical characteristics, with the result that the behavior of the system as a whole reflects an interplay between the characteristics of the components in isolation. Further, the individual structural units of biological systems tend to be soft: for example, the compression resistance of a protein network may be more than an order of magnitude lower than that of the air we breathe. While some of the mechanics relevant to such soft biomaterials has been established for more than a century, there are other aspects, for example the thermal undulations of fluid and polymerized sheets, that have been investigated only in the past few decades.

The general strategy of this text is first to identify common structural features of the cell, then to investigate its mechanical components in isolation, and lastly to assemble these components into simple cells. The first chapter introduces metaphors for the cell, describes its architecture and develops some intuition about the properties of soft materials. The remaining nine chapters are grouped into three sections. Parts I and II are devoted to biopolymers and membranes, respectively, taking a conventional reductionist approach, while acknowledging that the soft materials of the cell are anything but conventional.