No, it isn’t I. (I know! I was surprised too!)
In every organization, there is one person who is plugged into the pulse and knows who does what, what’s going on and when it’s happening, where everything is, how everything works, etc. In my personal experience, that person has always been a woman. (And, for what it's worth, it has never been me.)
Find this woman in your organization and make her your friend. She is an invaluable ally, perhaps the most important one, in helping you do your job well.