A magically book of spells and information, it acts as a spell focus. It can copy down any spell the user has casted, allowing for it to be recasted a number of times, using spell slots. It is attuned by writing your name in it but on must be able to cast magic, or else the name will fade. Only one person can be attuned to the book until that's person's death. The book pages upon that person's death  turn blank and allow a new person to sign its first page. Resistance to most forms of damage. It laughs in the face of fire. Once a spell has been cast or know the wizard's companion page magically fills in the details. It also will have information such as location of components, familiars, magical monsters, and magical items, and a few stories about the origins of magic, and the world. As a spell focus it allows for simple components and up to 50g to be bypassed but still needs verbal components. When casting it hovers in front of the user, magically flipping to the page of the intended spell. During casting while moving the user floats slightly off the ground, before landing. During reaction spells it allow the user to move 5 feet while casting, as long as they still had 5 feet of unused movement for that turn. It is said to have a will of its own, appearing as an old book in the humblest or strangest places at times, finding those it deems worthy or those in need. They are so rare wars have been fought over them and most believe it is just a legend. It is said that completing all its spells pages allows its user 'a true master of magical arts'  the ability to cast spells without using spell slots (at the regular level of the spell) or verbal compenets. It is unknown what is granted if all the pages are completed, rumors are unlimited power and riches. (Inspiration From Ni No Kuni) 

Notes: Immunity: All, Write your name on the first page and you are bonded for life, Utility, Sentient, Focus, transmutation