Loving maps as I do, I couldn't resist posting Thror's map here. As explained earlier, Gandalf, while on a reconnoitre in Dol Guldur, came across a dying dwarf in the dungeons. The dwarf placed a map and a key into Gandalf's safekeeping asking him to hand them to his son. It was many years later that Gandalf realised that he had been speaking to Thrain II and that Thorin was his son.
J.R.R. Tolkien used a variant of anglo saxon runes to compose the Dwarf Runes. The Tolkien Society has an excellent study pack related to runes here.
The company were able to ascertain that this map had directions to a secret entrance into Erebor. The instructions were in Dwarf runes at the side where the hand is.
In Chapter 3, as the company stays in Rivendell, Elrond is able to discover that the map contained moon letters which were rune letters that were only visible on the evening when there was a moon of the same shape and in the same season as the evening they were written. The runes on the map therefore were written on a midsummer's eve when a crescent moon shone behind them. They were written in silver pen using ithildin which was a derivative of Mithril and was used by the dwarves to decorate gateways, pathways and portals. The moon letters on Thror's map are written as follows:
if you enjoy cracking codes, here is the key to the runes from Tolkien Gateway.
There is a Runic translator here if you don't feel like translating a passage letter for letter.