The objective of this work is to provide an account, with appropriate detail, of some of the salient features of the development of the theory and analysis of engineering structures during the nineteenth century. There seemed to be two possible approaches to the subject: that whereby emphasis is on personalities and their contributions to the subject, or that whereby emphasis is primarily on subject development, with due acknowledgement of personalities and regard to the chronological aspect. Experience indicates that the former is conducive to some degree of repetition and confusion concerning the subject matter and, therefore, the latter approach is adopted (though personal names are used in subheadings to identify developments). But Chapter 6 is unique in being devoted to Levy's little-known, though highly-significant work on theory of frameworks. Free translation of original material is used extensively throughout the book in order to avoid misrepresentation or serious omission. Also, original notation for mathematical analyses are preserved as far as possible.

Chapters 4 and 11 differ from the others in being little more than brief reviews of topics which, though important, are peripheral to my purpose herein. The former embraces graphical analysis of simple frameworks which, together with the vast subject of graphical analysis of engineering problems generally, has very limited relevance to the features with which this work is concerned and which have determined the development of modern theory of structures.

The following is an abridged version of the author's free translation of Navier's Obituary Notice of 1837, by Prony, which is included in the 1864 edition of Navier's Leçons, edited and with additional notes by Saint-Venant.

Much progress in theory of structures during the nineteenth century has been ascribed, notably by Clapeyron (1857) in France and Pole (Jeaffreson, 1864) in Britain, to the coming of the railway era. But the state of knowledge of the subject at the beginning of the century was ripe for rapid development due, for example, to Coulomb's remarkable research in applied mechanics. Early in the century Navier began to contribute to engineering science encouraged by his uncle, M. Gauthey, Inspector General of bridges and highways in France. Navier was born in 1785 and orphaned when he was fourteen years of age. He was adopted by Gauthey whose book on bridges he published (1809) and revised (1832), following his education at L'Ecole Polytechnique and then at L'Ecole des Ponts et Chaussées, from where he had become ingenieur ordinaire in 1808. He may be regarded as the founder of modern theory of elasticity and its application to structures and their elements. The year 1826 is memorable for the publication of Navier's celebrated Leçons as well as for the completion of Telford's remarkable wrought iron chain suspension bridge at Menai (it was also a year of sadness for Navier due to failure, prematurely, of the Pont des Invalides, a Paris suspension bridge which he had designed).