Mnemonic (Warlock)

You know two additional 1st level spells, which are copied down in your spell book. These spells do not count against your total number of spells known, however you cannot swap out these spells once they are chosen. 

• When you choose this feat, you acquire a spell book holding two 1st-level spells of your choice. You must choose your spells from your class's spell list. You must have your spell book to cast these spells. Excluding your two first level spells acquired from this feature, you can never have more than 25 spells prepared per class per day (in other words, you can never have more than 25 spells per class plus your two 1st level spells prepared- a total of 27 spells altogether). 
• If you come across a spell in written form, such as a magical spell scroll or a wizard's spell book, you might be able to add it to your spell book. The spell must be on your spell list, and the spell's level can be no higher than half your level (rounded up). The process of copying the spell into your ritual book takes 2 hours per level of the spell, and costs 50 gp per level. The cost represents material components you expend as you experiment with the spell to master it, as well as the fine inks you need to record it.
• You may make a copy of your book in case the original is lost or damage. In the event that both the original spell book, and copy are lost and/or destroyed. Roll a Intelligence or Wisdom saving throw to see how many spells you remember, at the discretion of the Dungeon Master, to begin making your new spell book. You will need to find new resources, and spend more time and gold to recover lost spells into your new spell book. You will always know the two 1st level spells you picked. 

Note: Go to manage feat to add more spells beyond your two 1st level spells (third option) so that the spells are added to your character sheet. It's up to you to keep track of how many of your spells you can use per day, and the other rules that go with this feat.