The Reminiscences and Recollections of Captain Gronow : being "Anecdotes of the camp, the court, and the clubs at the close of the last war with France" and "Recollections and anecdotes."
Reread these for pleasure, after some years. Gronow was a professional dandy, who was quite young at the time of the Regency, so his reminiscences are in fact colored by later experience--he gets some of the language wrong . . . in the same way that Georgette Heyer does. All of a sudden, a lot of Heyer's Regency tales spring into focus after I reread this. For example, Gronow talks about the bon ton, a phrase that I haven't found anywhere before the 1820s or so, though the OED gives an example or two. "Ton" during the Regency--in all the letters and diaries, and in Jane Austen--meant style, it was not a designation for the Upper Ten Thousand until later.
I know, picky picky picky. Gronow is far more entertaining than Harriett Wilson; his style is wry, the details fascinating. But then Wilson was writing to defend herself (and to make money) and Gronow was just reminiscing. He was also witty, and Wilson . . . wasn't.
Anyway, highly recommended for anyone who loves Regency era romances and comedies of manners.