If you have completed the quest A kingdom Divided you will get this Book of Dead. This is the upgraded and improved version of Kharedst´s memoirs.  This book is a lot more useful than the original. It has up to 60 teleport charges, it also gives a plus 6 magic bonuses and a very nice plus 3 prayer bonuses. You will need to take the same steps to recharge the book if you run out of teleports.  If you lose this book, you will need to go to the NPC named Fullore. He is a commander that you can find on the first floor of the large castle of Kourend.