A young London doctor takes in a lost dog, and the search for its owner leads him through the lodging-houses, the dog-stealers and the poor of the city. Ballantyne wrote it in 1881 with a purpose-the trade in stolen dogs was real and lucrative-and let the dog carry the plot. The comedy is genuine and the ending settles a question about property that the book has been raising all along. Fifty-four plates of moonlit London streets and river views by painters including John Atkinson Grimshaw and James Baker Pyne give the doctor's night-time rounds their true atmosphere.