The building blocks of the known Universe are stars. To study what governs the structure and evolution of our galaxy, the Milky Way (MW), means to observe and understand the processes that govern the stellar birth, evolution, death, and motion over their evolutionary time-scales. The process of collecting detailed data on our Galaxy represents the first step in this work of archeological research and surveys such as Gaia, SDSS, APOGEE2, RAVE as well as forthcoming missions and telescopes such as SDSS-V, LSST, JWST, GMT, TMT will project us into a golden age of the MW research. Exploiting datasets of this scope is not merely a case of applying the same tools that have been used historically. It demands the development of, and experience with, leading-edge multi-dimensional data mining tools, as well as sophisticated methodologies to transform models from the “simulation space” into the “observational plane.” I will review the open questions in the research on the MW, and the theoretical challenges that we are going to face in the forthcoming years through the use of a novel concept of stellar populations and with a focus on the MW, its Local Group dwarf companions, and M31.