How did robert novak give away a CIA agent's identity

How and when did he give away the identity of a CIA operative for political motives?

Meaning, what is the story behind it. When did he do it & where did he get the info.

This article should sum it up.

It should have, but it doesn’t. It’s taken a special prosecutor with a grand jury two years to start to get to the bottom of it.
Matt Cooper’s Source, from BEFORE the Novak article came out (Newsweek, Today):