A nice article on gluing wood can be found at :

    http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch09.pdf

This article describes bonding properties of various glues, different
woods, surface preparation, and provides an extensive set of technical
references for those who would like to know more.  There are quite a
few other articles on specific adhesive types at the same Forest
Products Lab (FPL) web site.  FPL is run by the U.S. Department of
Agriculture (USDA) and, while it caters to the big timber company
interests, it is usually fairly objective.  Be warned that their
interests run to plywood and gluelams, not fine furniture or player
pianos!

Like Craig, I like and use hide glue a lot, and certainly think it is
by far the most appropriate adhesive for many piano rebuilding tasks.
That said, there are roles for many other kinds of adhesive in the
shop.  When assembling complex casework alone, the long open time of a
urea-formaldehyde glue can be a life- and project-saver.  For general
glue-ups of joints you don't intend to take apart, a yellow PVA type
glue is cheap, convenient, and strong.  Nothing beats thick cyano-
acrylates for gap filling and crack repair on wood turning projects
still on the lathe.  If things are going to get wet I'll take a
resorcinol or epoxy every time.

All of these glues, when used properly on a well prepared, well
engineered joint, are much stronger than the wood they are joining,
so arguments about strength (of the kind that proceed endlessly in
forums like rec.woodworking) are best left to the engineering geeks.
At least I've never broken a joint at the glue line -- the wood always
fails first, end grain joints aside.  The other properties of adhesives
-- sandability, flexibility, open time, water resistance, cleanup,
interactions with finishes, reversibility, etc. -- are probably much
more important in ones choice than strength.  "Best" is only in the
context of a specific application.

I think Craig has done us a service with his stout defence of hide
glue, certainly among modern woodworkers it is under-appreciated.
I am happy to have a wide range of choices including both modern and
ancient solutions

Cheers!

Roger Wiegand
mailto:rwiegand@earthlink.net