I-Spy

The I-Spy books were spotter's guides written for English children, particularly successful in the 1950s and 60s.

The company, "an organisation innocently insulting of North American aboriginal peoples", was supposedly run by a Red Indian chief called Big Chief I-Spy: better known as Camden antiques dealer Arnold Cawthrow. Members were called Redskins, and the head office was the 'Wigwam-by-the-Green', to which children could send their completed books and receive a feather in return.

The tribe was based on the I-SPY Books, 40-odd small volumes that sold in hundreds of thousands. ... Each book covered a subject such as I-SPY Cars, I-SPY on the Pavement, I-SPY Churches, I-SPY on the Railway etc. As you spotted objects such as coalhole covers, oak trees, semaphore signals, fire engines, whelks and so on you recorded the event in the relevant book, and gained points. Once the book was complete, you sent it to Big Chief I-SPY for his seal of achievement.

[text from Ralph Mills site linked below, needs a rewrite]

The books became very popular, with print runs well into six figures. In the early 70s, Chief I-Spy was joined by "Hawkeye", Ralph Mills, whose own web page is linked below.

I-Spy books are still being sold, by Michelin Travel Publications.