This package supports a flexible, arbitrarily high level of numeric precision -- the equivalent of hundreds or even thousands of decimal digits (up to approximately ten million digits if needed). Special routines are provided for extra-high precision (above 1000 digits). The entire library is written in C++. High-precision real, integer and complex datatypes are supported. Both C++ and Fortran-90 translation modules modules are also provided that permit one to convert an existing C++ or Fortran-90 program to use the library with only minor changes to the source code. In most cases only the type statements and (in the case of Fortran-90 programs) read/write statements need be changed. Six implementations of PSLQ (one-, two- and three-level, regular and multi-pair) are included, as well as three high-precision quadrature programs. New users are encouraged to use this package.