Bit::Vector is an efficient C library which allows you to handle bit vectors, sets (of integers), "big integer arithmetic" and boolean matrices, all of arbitrary sizes. . The library is efficient (in terms of algorithmical complexity) and therefore fast (in terms of execution speed) for instance through the widespread use of divide-and-conquer algorithms. . The package also includes an object-oriented Perl module for accessing the C library from Perl, and optionally features overloaded operators for maximum ease of use. . The C library can nevertheless be used stand-alone, without Perl.