5) The Lost Tales (I & II) - No you're just getting silly.
Oh, not nearly silly enough... because so many more books await the true Tolkein nerd. Anybody other than me read all these?
6) The Lay's of Beleriand (III)
7) The Shaping of Middle Earth (IV)
8) The Lost Road and other Writings (V)
9) The Return of the Shadow (VI)
10) The Treason of Isengard (VII)
11) The War of the Ring (VIII)
12) Sauron Defeated (IX)
13) Morgoth's Ring (X)
14) The War of the Jewels (XI)
15) The Peoples of Middle Earth (XII)