Once per 100 year, this book can grant one wizard, who spends 24 h, non-consecutive, studying this book, the following abilities:

• You may copy abjuration spells into your own spellbook for half the normal time and half the normal cost
• When you cast an abjuration spell, you may take a part of said spell to craft a defensive ward, which has hit points equal to: twice your wizard level + your intelligence modifier 
  • Whenever you take damage, this ward takes damage instead, if the ward is reduced to 0 hit points, you take any remaining damage (this ward may be considered temporary hit points)
  • If you cast another abjuration spell before your next long rest, the ward regains hit points equal to twice the level of the spell
  • The ward cannot be recrated before you've had a long rest, only regain hit points through use of abjuration spells
• May use the arcane ward (see above) to absorb damage that would affect another creature within 30 ft of you, this requires you to use your reaction and you must see the creature. The ward then takes the damage, but if the ward is reduced to 0 hit points, any remaining damage is taken by the intended target

This spellbook, contains all abjuration spells that are known to the world. But they need to be transcribed into your own spellbook in order to be castable.