The sequel to the 2005 hit is just what you would expect: more casual, sometimes cheesy, and invariably fascinating explorations into human (and, in the epilogue, capuchin) behavior. Levitt and Dubner deserve credit for popularizing the notion that economics is not all pie charts and interest rates. Here you will find a (meticulously researched) price list for prostitution services in Chicago, an analysis of the risks of drunk walking (with the intentionally scandalizing conclusion that driving is safer, for the drunk), and a revealing reinvestigation into the murder of Kitty Genovese showing that the psychology textbook case of the Bystander Effect was probably much exaggerated.

There are also sections on the male-female wage gap, terrorism, and climate change. These are necessarily more speculative, but still provide helpful talking points in case you run into someone who has all the answers for one of these issues. A section on talent, showing that top performers often enjoy hidden advantages such as a good birthday month or a last name starting near the beginning of the alphabet, was mostly scrapped after several books appeared on the subject, such as Outliers. (The notes indicate that the authors worked with competitive eating champion Takeru Kobayashi for this section. Other heroes mentioned in the notes but not the index: Dr. Sherwin Nuland, author of How We Die, Atlantic and Vanity Fair author William Langewiesche, and Neal Stephenson. There is also a mention of the Ellsberg Paradox and a great quote: "Facts, like jade, are not only costly to obtain but also difficult to authenticate." One ignores book notes at one's peril.)

I look forward to UltraFreakonomics. I have no objection to a disorganized collection of material, full of revealing data and great stories. One of my favorite stories is the crisis of equine transportation, which gets a couple pages of attention in the introduction. I first read of this in Simon where the wonderous passage below was quoted (from H. B. Cresswell in the Architectural Review, 1958).

The Strand of those days...was the throbbing heart of the people's essential London...But the mud! [a euphemism] And the noise! And the smell! All these blemishes were [the] mark of [the] horse....

The whole of London's crowded wheeled traffic - which in parts of the City was at times dense beyond movement - was dependent on the horse lorry: wagon, bus, hansom and `growler', and coaches and carriages and private vehicles of all kinds, were appendages to horses...the characteristic aroma - for the nose recognized London with gay excitement - was of stables, which were commonly of three or four storeys with inclined ways zigzagging up the faces of them; [their] middens kept the cast-iron filigree chandeliers that glorified the reception rooms of upper- and lower- middle-class homes throughout London encrusted with dead flies, and, in late summer, veiled with living clouds of them.

A more assertive mark of the horse was the mud that, despite the activities of a numberous corps of red- jacketed boys who dodged among wheels and hooves with pan and brush in service to iron bins at the pavement-edge, either flooded the streets with churnings of `pea soup' that at times collected in pools over-brimming the kerbs, and at others covered the road-surface as with axle grease or bran-laden dust to the distraction of the wayfarer. In the first case, the swift-moving hansom or gig would fling sheets of such soup - where not intercepted by trousers or skirts - completely across the pavement, so that the frontages of the Strand throughout its length had an eighteen-inch plinth of mud-parge thus imposed upon it. The pea-soup condition was met by wheeled `mud-carts' each attended by two ladlers clothed as for Icelandic seas in thigh boots, oilskins collared to the chin, and sou'westers sealing in the back of the neck. Splash Ho! The foot passenger now gets the mud in his eye! The axle- grease condition was met by horse-mechanized brushes and travellers in the small hours found fire-hoses washing away residues....