This talk will open the minisymposium "Multi-Physics and Multi-Scale Simulations with the Coupling Library preCICE", introduce the main concepts of the open-source coupling library preCICE (https://precice.org/), demonstrate the first steps in coupling a simulation code, and give an overview of current developments and research directions. preCICE is an open-source coupling library and ecosystem for general partitioned multi-physics and multi-scale simulations, including surface and volume coupling. It offers a selection of efficient numerical algorithms for surface and volume coupling (such as interface quasi-Newton acceleration, RBF-based space interpolation methods, and waveform iteration), it is designed for high-performance computing, and it is supported by a team of maintainers and a growing community. An API in C++ and language bindings in C, Fortran, Python, Julia, Matlab, and Rust allow coupling in-house codes from various application backgrounds. The coupling ecosystem of preCICE already includes ready-to-use adapters for established open-source simulation codes, such as OpenFOAM, FEniCS, CalculiX, deal.II, DuMux, G+Smo, MercuryDPM, Nutils, or SU2. Further tools allow coupling to system codes written using the Functional Mock-up Interface (FMI) or coupling one-to-many micro-macro simulations.