This interesting card set was based on the popular spy-spoof TV series of the 1960's starring comedian Don Adams. The regular cards featured black-and-white photo stills from the series, while the Secret Agent Kits were little disguise items, such as weird eyes or a fake moustache, in color and die-cut for kids to use in pretend play.
What sets this card set apart from most other Topps issues is the fact that the regular-size cards were issued in their 5-cent pack in such a way that each pair of cards was attached on one side, with perforation between them, making them basically a panel card set. What's more, many of the cards were cut and perforated imperfectly, resulting in varying card sizes between the pair. The Secret Agent Kits were distributed one to a pack.
The card backs offered a Get Smart Quiz where a question was asked and, to find the answer, the user was instructed to rub a coin over the central image, which was printed in clear ink but which became visible thereby (although the span of time since 1966 has caused many of these to become visible anyway). Along one side of the card back (depending whether the card were to the right or left, as part of the two-card panel) was the card number and a thin illustration of a secret agent character peering around a corner, gun in hand.
The backs of the Secret Agent Kits had a small illustration of a boy wearing several of the goofy disguise pieces, and a brief description of the particular disguise pictured on the obverse side.