Names used are actual names, unless indicated by an asterisk. Work in progress.

Actual item name (Level)
Simple Tome (Level 1)
Secret Tome (Level 2)
Magic Typewriter (Level 3)
Mystic Printer (Level 4)
Chest of Tomes (Level 5 – Regeneration time is 20 minutes)
Shelf of Tomes (Level 6)
Floating Tomes (Level 7 – Regeneration time is 40 minutes or 53 coins)
TBD (Level 8)

The number in parenthesis represents the number of purple gems, if you decide to sell that item.
2x Torn Papers = Magic Documents
2x Magic Documents = Magic Folder (1 gem)
2x Magic Folder = Book of Witchery (2 gems)
2x Book of Witchery = Book of Knowledge (3 gems)
2x Book of Knowledge = Book of Necromancy (4 gems)
2x Book of Necromancy = Book of Healing (5 gems)
2x Book of Healing = Strapped Books (6 gems)
2x Strapped Books = Book of Life (7 gems)
2x Book of Life = Book of Doom (8 gems)
2x Book of Doom = Phone of Magic (9 gems)
2x Phone of Magic = Tablet of Spells (max level; 10 gems)

BONUS ITEMS: (The number in parenthesis represents the number of purple gems, if you decide to sell that item.)
2x Ink and Feathers = Enveloped Letter
2x Enveloped Letters = Simple Scroll (1 gem)
2x Simple Scrolls = Magic Scroll (2 gems)
2x Magic Scrolls = Majestic Scroll (max level; 3 gems)