Infamously bad in the Twain canon - and still pretty bad even when you consider that. Both of these were written because Twain wanted to get paid, and it shows. They attempt to satirize common trends of the time (detective stories and travel/adventure stories), but they fail to actually be funny while also just being miles away from the grounded, down-home life that is idiosyncratic to Tom Sawyer. Don't read unless you just *have* to check out everything by Twain.