This spellbook, along with anything written on its pages, can't be damaged by fire or immersion in water. In addition, the spellbook doesn't deteriorate with age. 

Ex Post Facto Retroactive Preparation. When you choose which spells to prepare for the day, you can choose to prepare one less than your maximum. As a bonus action, you can choose one spell in your spellbook that you do not have prepared and instantaneously prepare it. This spell becomes a part of your prepared spells until you finish a long rest. 

Fortune's Favor. Once per day, you can cast Fortune's Favor without expending a spell slot.

Curse. Once you attune to this spellbook, you can't use any other spellbook unless you are targeted by the remove curse spell or similar magic. 

Notes: Divination Wizard, Utility, divination