Stupid question - gl/glut.h ???

Hey guys,
Real stupid question, while reading the green book (OpenGl programming for the X window System) the book uses commands from the gl/glut.h header file. I was looking through my includes and I do not seem to have this headder file in my library of header files. Does anyone know where I can get it? Does it even exist? The blue book has no mention of glut… functions, that is why I am wondering!!

Thanks
Roach

Look here: http://www.opengl.org/developers/documentation/glut.html