The building blocks of a completed thesis are chapters. Yet if these blocks are to hold together they must themselves be effectively structured internally, so that they can bear a load rather than crumbling away under pressure. A first step then is to divide the chapter into parts. In addition, two elements of designing internal structure are commonly mishandled: devising headings and subheadings to highlight your organizing pattern; and writing the starts and ends of the chapter and its main sections. I discuss these three issues in turn.