The story begins with the early history of French and its origins as a fusion of dialects from four regions around Paris. The 16th century was key to its literary and political standardisation and promotion, and saw the creation of the French Academcy and the origins of purisme, the peculiarly French form of language purism.
The first wave of colonial settlements established French in the Caribbean and North America. And in the 17th and 18th centuries French became the language of international communication and culture, as "the language of genius" and of the salon.
In the 1790s a survey by the Abbé Grégoire found that, out of a population of twenty eight million French citizens, only three million spoke French well and maybe another six million could carry on a conversation; most spoke a mix of other languages and dialects. The French Revolution helped to spread the use of French, both inside France and outside. And the 19th century creation of a mass education system continued its consolidation — and reinforced its purist tendencies.
French had a different history in Haiti, Belgium and Switzerland. And in North America, separated from France by defeat in war, French-speakers in Quebec, Acadia, other parts of Canada, and Louisiana went their own way. Elsewhere, following the "second colonial push", the French imperial project didn't succeed in its policy of cultural assimilation, but did manage to create a French-speaking base in the colonies.
French culture and science, from Victor Hugo to the Suez Canal, have helped to make French attractive. More direct action has come from educational networks and organisations such as the Alliance française and the Alliance israélite universelle, created to help educate poor Jews in French.
The rise of English has seen the decline of French as the language of treaties and in other spheres, but it has retained standing as an international language. In many former colonies, in Africa, Lebanon and elsewhere, French has flourished and remains an official language, an everyday language, or both; in others, such as Syria and Indochina, it has not fared so well.
The second half of the 20th century saw a rise in French language activism in North America, which took different forms in Quebec, Acadia and Louisiana. At a different level, the Francophonie is an official organisation of francophone countries vaguely comparable to the Commonwealth, which had its antecedents in the 1950s but has been slowly increasing in prominence since then.
Looking at some current debates, Nadeau and Barlow describe the ongoing "struggle for standards" driven by clueless language purists; they consider neologisms, new sources for standards, changes in the policies of dictionaries, and so forth. Surveying language policies and international campaigns for "cultural diversity" clauses, they suggest that France is in some ways the obstacle, with Quebec and others leading the way. And they conclude with a consideration of possible futures for French.
The authors of The Story of French are journalists, not historians or linguists, and this is evident in their approach. Politics and culture take centre stage and there is little local socio-linguistics — I didn't come away with any idea of the contexts in which French would be preferred to Wolof (or Arabic) in Senegal, for example. More attention is also paid to vocabulary — easier to explain to those without a linguistics background — than to other aspects of language.
Nadeau and Barlow are also partisan participants in the debates and political processes they describe. They are cheerleaders for French, for French culture, for government and organisational activism to support its use, and for the approach to that taken by Quebec over that taken by France. There is some exaggeration here — Louis Pasteur apparently "invented modern biology", for example — and some careless errors — "most of the world's languages have an academy, institute, committee, council or commission that serves as the ultimate authority on standards" (Lardil? Miniafia?).
There's a six page "Selected Bibliography", broken into thematic sections, but the vast majority of the works in it are in French. For a book in English, it would have been more useful to emphasize English sources, perhaps even to list them separately.
These concerns make me reluctant to use The Story of French as a reference, but as a general introduction it works well. There was a wealth of information in it that was new to me, on the history of the Francophonie, the extent of French use in Israel, the history of Acadia, language politics in Quebec, and more. And I'm not aware of other popular books in English that cover the same material.