A slightly misleading title there, since it covers approximately from the Renaissance to modern times, the history of sweets -- the British term, the American one being "candy" a term which is just about obsolete in Great Britain.
In fact it opens with a discussion of what she is treating with, and the imprecise terms. And that she is not covering chocolate but rather the sorts of stuff you can do with sugar.
She treats the types of recipes individually, giving their histories individually, along with a lot of the chemistry and art of making sweets. An extensive review of soft ball, hard ball, thread, which are measures of sugar concentration (you drop a bit of it into cold water and see what forms spontaneously). From some notes, professionals used the hard-boiled temperatures but did not describe them in recipes for common folks, and treated them as a trade secret. To be sure, once you get high up, you face the danger of caramelizing, which prevents you from reusing the scraps by reboiling them, and burning. The types of sugar used. "Doctors" which is what they called ingredients that prevent sugar from graining (crystallizing), such as lemon juice and cream of tartar. The slow advent of the thermometer and the saccharometer, which measures the sugar concentration by the specific gravity.
And the specific types such as fondat, or pulled sugar, or liquorice and marshmallow (first used as cough remedies, or comfits (such as Alice handed out as prizes), and sugar paste, which has a historic problem with variable edibility. And colors, which were sometimes brilliant and toxic. They began cheap, and so low-class, about the time that confectioners had just discovered ways to make them safely. How the recipe for fudge was imported from America, and how its addition of chocolate and such things prevented graining from forming large crystals. Toffee vs. the American taffy, which appear to have a common root but to have diverged. Caramels, and how they have nothing to do with caramelization except through the colors. . . .
It also has recipes for a good number of the sweets she discusses.