The biblatex package is a complete reimplementation of the bibliographic facilities provided by LaTeX in conjunction with BibTeX. It redesigns the way in which LaTeX interacts with BibTeX at a fairly fundamental level. With biblatex, BibTeX is only used (if it is used at all) to sort the bibliography and to generate labels. Instead of being implemented in BibTeX's style files, the formatting of the bibliography is entirely controlled by TeX macros. Good working knowledge in LaTeX should be sufficient to design new bibliography and citation styles — there is no need to learn BibTeX’s postfix stack language. Just like the bibliography styles, all citation commands may be freely (re)defined. In fact, users need not remain bound to BibTeX for use with biblatex: an alternative bibliography processor biblatex-biber is available. Development of biblatex and biblatex-biber is closely coupled.