The study of planetary systems around nearby stars, and their similarity to or difference from our own solar system, addresses a basic, central question about humankind's place in the universe. The MAPS project will develop a new optics and camera system for the detailed study of planets orbiting neighboring stars. The program will probe the atmospheres and physical makeups of the planets. Results from this research are easily accessible, and can be inspirational to students considering a career in science or engineering. The MAPS program will also provide training, through an annual winter school, for young people just starting out in research. Hands-on training in building and deploying a system such as MAPS provides critical experience for developing new tools for scientific discovery. Using the 6.5m MMT telescope facility on Mt. Hopkins, Arizona, the planned MMT Adaptive optics exoPlanet characterization System (MAPS) will combine: (1) high spatial resolution to resolve imaged exoplanets and disks; (2) high spectral resolution to detect exoplanet atmospheric absorption lines in an unambiguous way; and (3) broad wavelength coverage to probe systems across the range of wavelengths, crucial for understanding the physical processes in exoplanet atmospheres. A core science project will be executed to derive the physical parameters of known exoplanets, as well as new targets identified by missions such as TESS. The MAPS program will provide a vibrant training ground for young astronomers interested in a deeper understanding of exoplanets and the underlying instrumentation. The MAPS team will develop and hold the ExoTech Academy, an annual winter school focused on training and academic development for students and early career scientists. The MAPS team will also leverage proven, institutional-level research education programs to recruit underrepresented and/or first-generation undergraduates who will gain a mentored research training experience by working on the project. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.