How does the OGL work?

[Eldritch_Ent]

Hey all! I have a few questions about how the 3.5 DnD Open Gaming License works, and have decided to ask for any explanations or links to them you might have. I mostly just need a few questions asked-

First, just what IS the OGL? I know it lets me, say, use the basic 3.5 ruleset and materials and such when making a book, with the exception of certain things like mind flayers and beholders. How does it work exactly?

Second, what's the limit on non-OGL materia? Obviously a publisher still can't even mention things like Illithids, but could they, say, make a feat that says
Prerequisite- Cloak Dance (XPH, Page XYZ) or something, or is even that too much?

Third, is it true that the 4th Edition OGL-type thing is far, far worse about what it does and does not allow?

[kamikasei]

The OGL is a legal document, and if you want to use it you'd be well advised to read it rather than rely on the advice of others. Advice is valuable, of course, but CYA.

[Duke of URL]

1) The actual text of the Open Game License accompanies all such products (example), so that will give you the specifics.

In general, when a product as a whole is covered under the OGL, it must specifically list the specific elements that are "product identity", which the terms of the OGL ban using in other products (without licensing it separately, of course). It also basically prohibits the use of trademarks.

2) Going with the above, as long as it is not included specifically as "product identity" or a trademark, you're probably OK. Probably. I am not a lawyer, so bear that in mind. Edit: Bear in mind that WotC typically trademarks the titles of their books.

3) The GSL is a different animal entirely. It's a combination of some aspects of the OGL and the old (now obsolete) d20 trademark license -- the general consensus is that it contains the worst aspects of each.

[Eldritch_Ent]

The OGL is a legal document, and if you want to use it you'd be well advised to read it rather than rely on the advice of others. Advice is valuable, of course, but CYA.

Well, obviously. But it doesn't hurt to ask others for some explanations for the curious. Plus I'm not actually planning on using it, I'm just curious ho wit works really. Soo... Yeah.

Edit- Honestly not trying to be rude, mind you, so sorry if I came off that way, I'm just sayin... Also, that helps clear things up. Thanks Duke of URL!