Heterogeneous magnetic superconducting systems (HMSS) represent a new class of nanostructures. They are made of ferromagnetic (FM) and superconducting (SC) pieces separated by thin layers of insulating oxides. In contrast to the case of a homogeneous ferromagnetic superconductor studied during the last two decades, the two order parameters, the magnetization and the SC electron density do not suppress each other. In HMSS, the interaction between the two order parameters is due to the magnetic field created by the magnetic and SC textures. Strong interaction of the FM and SC systems not only gives rise to a new class of novel phenomena and physical effects, but also shows the important technological promise of devices whose transport properties can be easily tuned by comparatively weak magnetic fields.