If it is time to move beyond your own world, pierce the veil of other planes, this may be useful.
Publisher's blurb: "This invaluable sourcebook provides DMs and players everything they need to create and run planar adventures and campaigns. Complete rules and guidelines for creating characters skilled at plane travel and world-hopping, as well as new prestige classes, feats, spells, and magic items. Comprehensive descriptions of several different portal types, including their traits, characteristics, and game statistics. Rules and guidelines for designing an endless variety of new worlds and planes. Guidelines for altering existing creatures to create planar variants, and complete descriptions of many new extraplanar monsters and allies."
More when I get hold of a copy!
Click HERE if you want to buy this book from Amazon.com or HERE
if you prefer to use Amazon UK.
Click HERE to get a PDF version from DriveThruRPG.com
Book Details:
Author: Mike Mearls
Publishers' Reference: DD44
ISBN: 1-58994-104-7
Hardback, 176 pages
Date: November 2003
Product page last updated: 31 December 2005