tends toward increased ``intelligence''. This is obvious when we think about adding definitions, theorems and methods to the library. It is less obvious and more noteworthy that other changes move it in this direction as well. For example, it is helpful if the system is aware of what is in the library and what users are doing with it. It is good if the user knows when to invoke certain tactics, but once we see a pattern to this activity, it is easy and natural to inform the system about it. Hence there is an impetus to give the system more knowledge about itself. This is related to recent themes in the field of artificial intelligence [Bundy 83,Charniak & McDermott 85,Davis & Lenat 82].