What is the oldest complete book written in braille?
Some sources claim that the first Braille book was published in 1829, others in 1837. The answer appears to depend on whether you are looking for a book that contained text in Braille's six-dot system or a book produced entirely with that system.
Braille trimmed the raised dots [from Charles Barbier's system of night writing] to six, further honed his system, and published the first braille book in 1829.
Source: More Than Ramps by Lisa I. Iezzoni et al (Oxford University Press, 2006). Quoted from a text adapted from American Federation for the Blind: "What Is Braille", accessed August 2004. (Note that this link is no longer up to date and that the AFB's current page What Is Braille? now contains different information.)
While the blind students at the institute [Haüy's school for congenetally blind children, later renamed to the National Institute for Blind Youth] took quickly to the Braille method of writing (in 1837 they published the first Braille book in the world: a history of France in three volumes), it was slow to catch on with school authorities. The assistant director of the school, P. Armand Dufau, was dead set against the Braille system, claiming that it made the blind "too dependent"; he preferred instead a system invented by the Scotsman John Alson. To ensure that Alston's system and not Braille's would be adopted, Dufau burned the school's entiry library—Haüy's raised-type books as well as all the Braille books he found.
Source: For the Benefit of Those Who See: Dispatches from the World of the Blind by Rosemary Mahoney (Little, Brown, 2014).
The first Braiile book was published in 1829.
Source: Mass Notification and Crisis Communications: Planning, Preparedness, and Systems by Denise C. Walker (Taylor & Francis, 2011).
According to the AFB's current page on Books in Braille (accessed 26.01.2022),
In 1829, the Institute published Louis' book, Method of Writing Words, Music and Plain Songs by Means of Dots for Use by the Blind and Arranged for Them. In it, Louis explained how his code worked to produce letters, words, punctuation, capitalization, musical notes, and arithmetic symbols. The book was prepared using embossed type, but examples were provided in Louis' six-dot code. (…) In 1837, the Institute for Blind Youth produced the first full-length book published in braille, Precis Sur L'Histoire De France [A Brief History of France]. A copy of the book, one of only three extant copies, is preserved in the Rare Book Collection of the American Foundation for the Blind and is illustrated here.
This suggests that Louis Braille's book from 1829 was not entirely in Braille; most of it was in embossed type, of which Moon type is a somewhat more recent example. (Moon type was invented some time after Braille's raised dot system. It is easier to learn for people who have lost their vision after learning to read print, but also more difficult to produce.) The 1837 history of France appears to have been the first book entirely in Braille.
However, other types of embossed or engraved writing had been in use before Braille's invention and the adoption of Braille's system did not exactly happen overnight:
The earliest form of embossed or engraved writing for the blind was invented by a Spaniard, Francesco Lucas, in 1604. By the beginning of the 19th Century, there were some 23 different methods of embossed writing in existence. It is small wonder that the adaptation by Louis Braille of a "night reading" system of raised dots invented by a French cavalry officer, Charles Barbier, did not cause a stir. It was not until two years after Braille's death, in 1852, that it was officially recognized in Paris. (…)
The acceptance of the braille system has never been easy or swift. In the United States it required a "war of the dots" among several competing systems, all of which had merit, before agreement on the use of braille as the standard medium was achieved in the 1920's.
Source: A Guide to Developing Braille and Talking Book Services by Dina N. Bedi and John M. Gill (De Gruyter, 2013).