If it's not been updated in a while - and Scanner Master sells several books in this category - it's not going to be all that useful. Besides you have numerous other sources of information - Glenn Hauser's World of Radio (and the associated DXLD Yahoo group), Prime Time Shortwave (its frequency lists are updated every 3 or 4 weeks or so) and the NASWA Journal (the monthly pub of the North American SW Association), just to name a few.
73s Mike