gtk+10 vs. gtk+: what's the difference

[Darrin Tisdale/Cambridge/IBM<dtisdale omotech com>]

I have been recently getting used to Linux (a job in itself) and I found 
that some of the tools (like gtk+-1.1.2) want gtk+10.  I have gtk+-1.0.0-1 
installed, but it still complains about gtk+10.  When I found a makefile 
from a CVS system on line, the make file tells me that there is a conflict 
with gtk+-1.0.0.  Further investigation revealed two other interesting 
things:

1) they don't like each other
2) some items want gtk+10, some want gtk+

So, what can I do?

1) where can I get gtk+10?  every place I look I only find the make file.
2) what is the difference and can they exist peacefully on my Linux box?
3) why are there differences?

 . . Darrin Tisdale
Weaning myself from Windoze, day be day . . .