The theory of shell structures is a large subject. It has existed as a well-defined branch of structural mechanics for about a hundred years, and the literature is not only extensive but also rapidly growing. In these circumstances it is not easy to write a textbook. The character of any book depends, of course, mainly on the author's conception of its subject matter. Thus it may help the reader if I set out my basic views on the theory of shell structures at the outset.

Most authors of books and papers on the theory of shell structures would agree that the subject exists for the benefit of engineers who are responsible for the design and manufacture of shell structures. But among workers who share this same basic aim, a wide variety of attitudes may be found. Thus, some will claim that they can give the best service to engineers by concentrating mainly on the form and structure of the governing equations of the subject, expressed with due rigour and in general curvilinear coordinates: for once the foundations have been laid properly (they say), the solution of all problems becomes merely a mathematical or computational exercise of solving the equations to a desired degree of accuracy; and indeed unless the foundations have been laid properly (they say), any resulting solutions are of questionable validity. Another group will argue, on the contrary, that they can serve engineers best by providing a set or ‘suite’ of computer programmes, which are designed to solve a range of relevant problems for structures (including shells) having arbitrary geometrical configuration; and indeed that the provision of such programmes renders obsolete, at a stroke, what was formerly called the theory of shell structures.