Melodics: Violin
The violin has a rich heritage in Cuban music since the early colonial period in the island's western, where it interpreted dance genres like the Danzón and the Habanera. It is most commonly found in the charanga line-up partnered with the flute; a development that came out of the quest for a sweeter sound than that produced by brass-centric ensembles.

The charanga format, and hence the violin in Cuban music, reached its latest zenith of popularity during the world-wide chachachá boom in the 1950s. It is now a mainstay instrument of a number of popular salsa and timba bands: Orquesta Aragón, Orquesta Broadway, Africando and Los Van Van to name just a few.

Like the guitar and piano, the violin's role is divided between playing the repeated rhythmic progression called the guajeo (or montuno), providing melodic accents and soloing. How much emphasis is placed on each depends on several factors like the line-up, the arrangement and the type of music.

The instrument
What to look out for when purchasing a violin, acoustic or electric, is well beyond the scope of this page. Indeed there are pages in other parts of the web that are better suited to this purpose. However, when it comes to pickups, I can recommend the Fishman Acoustic Instrument Pickups and Preamps like the V-100 and the Pro-EQ II respectively.

What to play
In order of importance is providing a guajeo, followed by being able to add or quote short riffs, and then soloing. Easily the best reference book which can help you do all of this is the excellent 'Latin Violin: how to play salsa, charanga and Latin jazz violin' by Sam Bardfeld (formerly of Los Jovenes Del Barrio).

You may want also to explore the resources available for guitar and piano, details of which can be found on the relevant pages of this section.
 

Recommended Resources

Salsa Guidebook For Piano & Ensemble by Rebeca Mauleón. (External link)

Latin Violin: How To Play Salsa, Charanga and Latin Jazz Violin, Book & CD Package by Sam Bardfeld. The definitive instructional package on Latin Violin. (External link)