Chamber of Mazarbul
- It is likely that the Chamber of Mazarbul once served some great ceremonial purpose in the old days of Moria; now it remains the tomb of Balin, son of Fundin and friend to old Bilbo, who, not so many years ago, led an expedition much like the current one to retake Moria and restore it to the glories of old. Alas that his efforts came to ruin so final that none ever returned to their homes to tell the tale of it, and only now has the truth been learned.
- Book of Mazarbul is found in this Epic quest.
- details the writing of Book of Mazarbul
- The lore-masters of Khazad-dûm were revered for their detailed record-keeping, though much of their old knowledge vanished when the Balrog awoke and the goblins of the Misty Mountains flooded into Moria’s halls. One of the chief repositories of dwarf-lore was the Chamber of Mazarbul, a hall of records located on the Seventh Level, just north of the vast Twenty-first Hall.
- In later years, when Balin of the Lonely Mountain and his company entered Moria and attempted to retake their home of old, the Chamber of Mazarbul became a shelter for them, and served as their last bastion when their efforts failed. The Chamber became Balin’s tomb, and the last record of his Company lay there with him, awaiting the arrival of those who might share the tale of his fate with his kindred in Erebor. 
Here is how it appears in the books, along with Reddhawk's translation:
The runes above the red letters represent Khuzdul and are written in Angerthas Moria, while the runes above the blue letters represent English (Westron/Common Speech) and are written in Angerthas Erebor. The bottom runes are a common translation of the upper runes. As you can see, the uppers runes translate as:
The lower runes represent the common translation of this:
Keep in mind that the runes represent sounds. That is why you see "SUN" in place of "SON" and "OV" in place of "OF".
The Book of Mazarbul
From another wonderful post by Reddhawk:
As you can see, the runes were rather difficult to make out. The first word was especially hard to read. Fortunately, by enlarging the photos I was able to decipher them. As with most of the runes in Moria, these are Angerthas Moria. As you can see the runes spell out "Katûb Mazarbulu". The second word is instantly recognizable and means, "of Mazarbul". Just as with the inscription on Balin's tomb (uzbad khazaddûmu ~ lord of Moria), the -u ending means "of". Although it does not seem to appear in any Khuzdul word list that I know of, the first word, "Katûb", must clearly mean "Book". I can only conclude that this is a Neo-Khuzdul word construced by Turbine for their use in Moria.
Aside from this obvious example, the translation of "Katûb" as book is further attested to by its use throughout Moria. There are several place names containing this word, such as "Mezel-katub" and "Katub-zahar". Each of these are the names of places that appear to be libraries or archives. Indeed, I believe the name "Katub-zahar" very nearly means "library". We know from the Dwarvish name of Nogrod, Tumunzahar (or "Hollowbold"), that "zahar" means "bold" or "building". Thus, "Katub-zahar" would appear to mean literally "Book-building" or more figuratively, "library".