The default windows API functions to load external libraries into a program
LoadLibraryEx) only work with files on the filesystem. It's
therefore impossible to load a DLL from memory.
But sometimes, you need exactly this functionality (e.g. you don't want to distribute a lot of files or want to make disassembling harder). Common workarounds for this problems are to write the DLL into a temporary file first and import it from there. When the program terminates, the temporary file gets deleted.
MemoryModule is a library that can be used to load a DLL completely from
memory - without storing on the disk first.
doc/readme.txt for more informations about the format of a DLL file and
a tutorial how they can be loaded directly.