This should have been made a decade ago. It lets you use your C compiler's native 64 bit integers with 32 bit perls. Nearly all 32 bit perls are compiled with compilers that natively have 64 bit integers so this module works in nearly all 32 bit perls. It uses operator overloading, unlike its competitors, so your code still looks normal, and there is a lower risk of accidental truncation to doubles. The docs could be slightly better, but the function names are self explanatory. Its perfect IMHO.