Abstract Data Type
-  Encapsulates data 
 
-  Separates interface from implementation 
 
-  Implementation can change; interface remains 
 
-  Interface often specified in a formal manner 
 
Examples
-  Programming in the small:
	
 
-  Programming in the large:
	
	-  Relational database accessible via stored procedures 
 
	-  Data accessible via the web service model