What I like about Bruce [Stillman] and Tom [Kelley]'s work, (they're not probably now as good at this as they used to)-is starting with the whole problem. I mean that's what biochemistry does. Start with the whole problem and then you try to fractionate it and figure out how it works. I don't think there's any laboratory, and I'll put Tom and Bruce right together, that's done it better than those two. And then of course Bruce, sooner than Tom, has moved on towards other approaches and move into other models, yeast, molecular genetic approaches to try and figure out how replication works. I think Bruce has also been sooner to move toward-and I do think of them as Tom and Bruce-towards asking questions about regulation. I mean-how is it-not just what are the pieces of the replication machine-how is it regulated? How does it work? How does the cell know which is the start and which is the stop?