SMACSS (pronounced “smacks”) is more style guide than rigid framework. There is no library within here for you to download or install. SMACSS is a way to examine your design process and as a way to fit those rigid frameworks into a flexible thought process. It is an attempt to document a consistent approach to site development when using CSS. And really, who isn’t building a site with CSS these days?!
SMACSS is a wildly adopted process for maintaining large and small projects. The core principal behind SMACSS is it's ability to break things down into smaller parts and then rebuild.
The following sections will go into depth about how these principals work, but if you are into reading and want to listen to the man himself, watch this video series hosted at Adobe.