Title: Circumstellar Disks of Be Stars

Circumstellar disks of Be stars are thought to be formed from material  
ejected from a fast-spinning central star.
This material possesses large amounts of angular momentum and settles  
in a quasi-Keplerian orbit around the star.
This simple description outlines the basic issues that a successful  
theory of circumstellar disks must address:
1)    What is the mechanism responsible for the mass ejection?
2)    What are the energy sources and how the material attains the  
needed angular momentum?
3)    What is the final configuration of the material?
4)    How the disk grows?
With the very high angular resolution that can be achieved with modern  
interferometers operating in the optical and infrared we can now resolve
the photosphere and immediate vicinity of nearby Be stars.
Those observations are able to provide very stringent tests for our  
ideas about the physical processes operating in those objects.
In the first part of the talk I'll review the current theories of disk  
formation and evolution. In the second part, I'll bridge theory and  
observations to illustrate how present high angular resolution data  
are helping us to uncover the secrets of the Be phenomenon.