This is a good book for anyone interested in finding out more about some of the more interesting figures of Restoration-era England. Despite the fact that Norrington is prone to gush at times about the fascination and charm of letters that are, in some cases, little more than quickly dashed-off notes, as a body the collection is quite interesting.
Norrington's strength (and weakness) lies in her ability to string together the letters, filling in the context with incidents in the life of Charles II and his sister, Minette, the two main correspondents. Unfortunately, Norrington uses about a fifth of the footnotes I'd like to have seen. For every anecdote whose provenance she footnotes, there are four she doesn't. There is a bibliography, but some of the unfootnoted incidents are so so vaguely attributed in the text that I'd be hard-pressed to know where to begin searching them out in her sources. She includes no index, either, which is quite frustrating as well.
Still, it's a good read, and those interested in the Restoration would already be in Norrington's debt had she only assembled the letters and nothing more. The book is worth buying just on the strength of the letters, if you can find it for a reasonable price.
It should be emphasized that these letters are most interesting from a historical perspective, however, and not as masterpieces of the art of letter writing. For that, try Charles' and Minette's contemporary, Rochester, in Rochester's letters, edited by Jeremy Treglown.
[This review also posted on Amazon in the US.]