so she was -- the case is known as mariah martin and the red barn. and there's a puppet show about it. it was so successful it lasted, oh, i tracked it through the 1890s, and she died in 1823, i think. and the most amazing thing i discovered was that they named racehorses for murderers. and there were, i think, at least two or three racehorses named jack the ripper that were running while the murders were still going on. can you imagine going to race course, and jack the ripper's coming up on the outside. but they did it. >> host: judith flanders, you've referred to charles dickens as a streetwalker earlier, but speaking of streetwalkers, what's your book "sharp practice" about? >> guest: your researcher dug up a dead book. >> host: a dead book? [laughter] >> guest: it was a book i was going to write but then didn't. >> host: about margaret caroline rudd. >> guest: i long to write about mrs. rudd, but i had just started to do some research, and i was having a wonderful time. mrs. rudd was an 18th century forger, and the mail arrived one day, and so i