DFTB+ is a fast and efficient versatile quantum mechanical simulation package. It is based on the Density Functional Tight Binding (DFTB) method, containing almost all of the useful extensions which had been developed for the DFTB framework so far. Using DFTB+ you can carry out quantum mechanical simulations like with ab-initio density functional theory based packages, but in an approximate way gaining typically around two order of magnitude in speed. [see About DFTB+ for further details] DFTB+ is used worldwide, with more than 1000 registered research groups. It is free for academic, educational and non-profit research. You can download it after registering and signing a license agreement. Commercial use is possible upon individual request.