What's the reverse of Quaternion.AngleAxis?

Hi,

Given a Quaternion, is there a way to get the axis of rotation? I know that, given an angle + axis you can generate a Quaternion with AngleAxis, and you can get the angle of rotation of a Quaternion with Angle, but there doesn't seem to be a way to get the axis.

I also want to note that this is a duplicate of this question, but the asker prematurely closed it.