How to Play Spy Ring

About Spy Ring, from BoardGameGeek:

Players operate as both a spy and a contact man in an effort to collect as many secrets as they can from 16 Embassies in the newly created international city of Espiona. The one who collects the most valuable set of secrets is the winner. The newer (1970's) version of the game changed in quite a few ways, but still bore a great resemblance to the original. The newer version was more of a race to collect a set of secrets (reading them using a "decoder"), and the contact man became a bodyguard for your spy.