The PHILCO Phorum

The back 1/2 inch or so of the veneer is split off the top behind the door on the top. It's 2 pieces of 3 1/2" x 17 1/2" in a mirror image pattern. I'm thinking I would be better off replacing it with 1 7"x 17 1/2" sheet of straight/curly based in part on my lack of skill. And since it is disconnected and or above the surrounding woodwork, I wont have any matching problems per say. :

And how do you tell what kind of walnut it is? It is not carrying a birth certificate or passport.

In most cases they used some form of French walnut either straight or quarter sawn, sometimes they used stump or burl walnut but not usaully on a top I think that the best thing to do, if it's book matched, would be to cut a straight line parallel to the grain where the veneer splintered off and butt join a new strip (one with a similar colour and grain) along the back side. The Albert Constantine company has a gallery with photos of the various species of veneers they have available, it may help to identify what species was used in the top.
Regards
Arran