Often considered to be a "classic" book written by a Zouave officer who served in Algeria and the Crimean War, and often given undue prominance in the literature because it was translated into English (and thus one of the very few French sources available to anglophile/phone historicans) by an American as part of the 'Zouave-Manie' that developed there following the report of Geroge McClellan on the French Army in the Crimea and the press reports of W H Russell et al. The book charts the campaigns of the 2eme Zouaves and the daily life of the members of that regiment, providing a fascinating glimpse into the life of the French army on campaign.
However, despite being traditionally claimed to be authored by Jean Joseph Gustave Cler, it most certainly was not. Cler and his colleague Baron Pierre Albert du Casse (a French Staff Officer) collaborated on a book recounting the history of the 2eme Regiment des Zouaves (formed only in 1852) and its recent history in the Kabylian an Crimean campaigns, tapping into the 'Zouave-Manie' which was sweeping France. The work probably started in 1858 and it was published posthumously in 1859 as a memorial to Cler.
Du Casse states that he wrote the book based on the letters of Cler (those he sent to Marechal Castellane survive) and the regimetnal journal of the 2eme Zouaves which also survives in the French Army Archives at the Chateau de Vincennes, Paris. Du Casse also states that following the death of Cler his friends contributed material for the book and subscribed for its publication. IT appeared first in the 'Journal des Sciences Militaire' in part form during 1858 and this version differs greatly from that which finally appeared as a book. The first edition was published in 1859 and the second, revised editon in 1868. The first English translation was published in America in 1860.
So here we have a problem: the book was not writen by Cler. It was perhaps "ghost written" from his letters by Du Casse, and we can compare the surviving letters written by Cler to Castellane to corrobrate the accounts given in the book. Infact, huge chunks are copied directly from his letters as Cler had a very idiosyncratic style and always wrote in the 3rd person. However, and this is a big however, we do not know from what other material Du Casse was working: did Cler keep a diary? What else did his friends contribute to the book? We just do not know. Thus this book goes from being a primary source, 'written by one who was there' to a secondary source, worked up albeit from primary data, but in itself is not trustworthy. Rather like the volumes of 'Souvenirs' and 'Memorials' written many years after the event which are influenced by the fallible memory of the writer and anything else they may have read or persons spoken to which may affect what they remember or think they remember or think they know. They become rather like oral history, historical fiction rather than historical fact.
There we have it: 'Souvenirs d'Un Officier des Zouaves' is not a book written by an officer of Zouaves recounting his experiences but rather a book written about an officer of Zouaves and his regiment.