Non linearity

This is a problem with regression that I am most concerned with. I was hoping others here could tell me how they deal with it when they encounter it and how they test for it. I work with fairly large data sets so seeing it in the residuals is not easy.
Yeah I remember that, although I ended up not figuring out how to do it I think. It is in one of my tomes.

Could you send me the SAS code you use to test it? :p

I think an even bigger issue is how you deal with this problem if you find it. I have looked at various fixes and none of them had parameters, they were visual. I had trouble interpreting them and my audience would be worse.