It's not bad. Each page gives the book eight teleport charges for a maximum of 40. After completing the quest A Kingdom Divided, it transforms into the book of the dead. The book of the dead has 60 charges instead of 40.  The only problem is recharging the book requires 1 law, body, mind, and soul rune. If you're an Iron Man account, those costs are less than ideal. I would only use this to teleport to Port Piscarilius. Use Xeric's talisman and the Kourend Castle Teleport spell for the rest of the cities.