We gain information about the universe through analysis of the spectra from celestial objects. However, while the intensity spectrum represents a scalar quantity but electromagnetic radiation occurs in the form of transverse waves, the polarized spectrum provides us with a 4-vector, the Stokes vector. The increased dimensionality of information space opens new windows to the universe, in particular for the exploration of magnetic fields. It is well recognized that the magnetic field is a primary agent responsible for structuring and the source of all variability on intermediate time scales, which manifests itself in all forms of solar and stellar activity. It is therefore not surprising that every year there are many scientific meetings organized with the objective of studying the role of magnetic fields in cosmic objects. What is largely missing in these meetings is however an in-depth investigation of the foundational aspects of how magnetic fields can be determined by the means of spectro-polarimetry, our main gateway to cosmic magnetism. The primary aim of our series of Workshops is to address these foundational aspects, with less emphasis on the morphological and physical properties of cosmic magnetic fields. The theoretical foundations concern the physics of the interaction of radiation and matter in magnetized media, formation of polarized atomic and molecular spectral lines with the Zeeman, Hanle, magneto-optical and Paschen-Back effects, optical pumping, polarized radiative transfer with coherent scattering, hyperfine structure, quantum interferences, and partial frequency redistribution. The observational foundations concern the design and operation of high-precision imaging Stokes polarimeters, choice of observing parameters and strategies for trade-offs between resolutions (angular and spectral) and polarimetric precision, diagnostic techniques to minimize model dependence (use of differential effects like line ratios for the Hanle and Zeeman effects), strategies for data inversion, or the definition and initiation of synoptic programs for the Hanle effect. The series of Solar Polarization Workshops (SPWs) is the prime venue where scientists can come together to address these foundational aspects. They have taken place every 2-3 years in different parts of the world, starting in St. Petersburg (Russia) in 1995, followed by Bangalore (India), Tenerife (Spain), Boulder (Colorado), Ascona (Switzerland), and Maui (Hawaii), each representing a milestone in this fundamental and rapidly evolving field of astrophysics. The next (7th) Workshop (SPW7) will take place in Kunming, the spring city and the capital of the Yunnan Province in the southwest part of China. Yunnan Astronomical Observatory is located in Kunming and operates a new 1-m solar telescope located at the Fuxian Lake not very far from Kunming, and currently does the design and construction of the Fiber Arrayed Solar Optical Telescope (FASOT). During the Workshop visits to the Yunnan Astronomical Observatory and to its Fuxian Lake site will be organized on September 11, 2013. The various aspects of spectro-polarimetry that will be addressed are as much foundational for stellar as for solar physicists. Since the Sun serves as such a convenient astrophysical laboratory to explore the relevant physical processes in detail, the Workshops have tended to be dominated by solar physicists, in spite of efforts and a strong desire to involve the stellar and planetary communities as well. However, with the maturity of the field that has developed over the years, the many applications beyond the Sun are gaining in importance. It is therefore our hope that there will be a strong stellar and planetary (including exoplanets) representation at the meeting.