look <object> look <object> in <container>
Show a description of something.
The first form, with no arguments, shows you the name and description of the room you're in, along with a list of the other objects that are there.
The second form lets you look at a detail in a room, or a specific object. You can qualify this with an owner, such as 'look at Gilmore's gun' or 'look at my nose'.
The third form shows you the description of an object that is inside some other object, including objects being carried by another player.