La novela picaresca, as it is originally deemed in its native Spain, is a literary genre which gained extensive notoriety (and popularity as well) during the XVI century and extended throughout time until a sudden revival in the XX century.
The genre comes to existence during a historical context where Spain is going through tremendous chaos: there were upheavals regarding the monarchy, the church, the feudal system, foreign populations, and even in the arts. The world, as Spain knew it at the time, was crumbling around and, as a result, there was hunger, anger, chaos, and overall social dysfunction.
The picaresque became the "comic relief" of the times. The main character of picaresque novels is meant to represent a typical citizen who also happens to live in oblivion of the chaos surrounding him. Although the character is oblivious, at the same time, it suffers as a result of the circumstances.
This main character is either young, ignorant, or a simpleton. A classic example is El Lazarillo de Tormes, who is a pícaro (rascal, mischievous) little boy living in extreme poverty but who uses his wits to score, at least, a piece of bread.
Hunger and conflict are perennial themes in picaresque novels and poverty, corruption and injustice are ever-present. It is safe to say that these novels provided a much needed way of escapism from the unfair situation of the common folk by using as a mouthpiece the wits and malice of an everyday character who speaks on behalf of those who live in equally miserable circumstances.