I am visually comparing paper profiles using the curves tab of the Profile Manager. Different paper profiles produce different curves but I have no reference as to what I am looking at or what I should be looking for.
Would someone explain these curves and/or point me to a good read on the subject? Thanks.
As with any application, it is always a wise idea to RTFM. 
It’s explained in ColorWiki section of the Chromix website. Have a look here: colorwiki.com/wiki/Category:Tools
For the specific instruction manuals, check here: colorwiki.com/wiki/Category:Manuals for the general instruction manuals page. The following links I think you will also find quite helpful.
ColorThink Pro Curves:
colorwiki.com/wiki/ColorThin … Curves_Tab
Neutral Rendering Curves
colorwiki.com/wiki/ColorThin … ing_Curves
Finally, just a very quick explanation of what the curves are trying to show you, taken from the ColorThink Pro Manual1 “The Curves indicate what the profile needs to do, all along the spectrum of white to black, in order to produce neutral gray”.
Hope that helps mate.
RTFM???..How about BM?..that’s Bite Me. 
The first place I went was the FM that was delivered with the app and…I had to Google other inquiries just to find where the FM was…and then it was the FM for Version 2.0, dated 10/3/2002… and there was no mention of the curves tab in the Profile Manager section or any section…ANY QUESTIONS???
And…Thanks for the pointer to ColorWiki.
I really appreciate JJR’s input on this. I am shocked and appalled at how outdated that pdf is that we send with ColorThink 2. We have long ago moved to updating the manuals on the ColorWiki, and I supposed we just include the original pdf manual in the download because it’s there and because we figured some people might prefer the manual in a more tangible form. But while we’ve been on autopilot over the years, the software has upgraded and improved and changed its look. That old pdf of ColorThink 2.0 is embarrassing.
I have been in email discussions with the OP and several good ideas have come from this. (Some of these had already been planned for.)
And I am personally going to lobby for dropping the included pdf manual off the install package. Users can easily print the colorwiki manuals if they need to.