The violin makers and their work have always fascinated historians and musicologists who could thus study the codes and the functioning of a profession in constant evolution. They collected historic as well as social cultural information necessary to the comprehension of this activity, without ever differentiating guitar makers from violin makers. As the powerful corporations that, in the 18th century gave the status of “sworn master” to the best craftsmen, they classified instrument makers in several large generic categories; strings, organs, harpsichords and brass instruments. Until around 1760, there was no separation between guitar makers from violin makers, the same makers built violins, basses, quintets, viols, mandolins, harps, citers, guitars and hurdy-gurdies, that is, plucked and bowed strings. Inventories made in some violin making workshops – after the death of the violin maker – demonstrated this fact clearly by the stock of wood, inlays and uncompleted instruments remaining when the activity stopped. Except for the “Romanillos” and the “Antonioni” the dictionaries of violin makers – for the major part written in the 20th century – do not refer to the guitar, except in anecdotic ways, and often with contempt: read what Vannes wrote about Stauffer! : “..In spite of (…) all these efforts and research, he was never considered any better than a guitar maker…”. Or the awful calumnies that Henley wrote about the Pons brothers in the first edition of his dictionary that he suppressed afterwards. The documents that we could consult deal only with the repertoire, the music, the playing, the composition and the musical practice, the life of the composers or the musicians, but nothing about the techniques or technicians, nor instrument making. There are nevertheless some works about guitars made by luthiers, but dedicated mostly to our contemporaries, or the industrial American luthiers whose instruments are known the world over. About the golden era of guitar in Europe, apart a few statistics: corporation regulations, inventories after death, custom reports, craftsmen corporations, there is practically nothing. This is an omission we would like to correct. Since we have been “educated” by a profession that has for a long time been practicing the delicate art of expertise as well as the none less delicate art of restoration and since there is no tradition, method, or school dedicated to the instrument we are dealing with; since the role of museums is to conserve the instruments in their actual condition, we thought we would like to try and find the filiations, the 2 influences, trainings, styles or schools that could be pertinent to apply to our research and the working techniques of the makers of the string quartets: observations, doubts, comparison, drawings, identification, double checking, classification of the information, etc…