Although soil spectroscopy was established as a discipline in the twentieth century, it has only become practical in the last decade, because electro-optic technology now enables producing high-quality data from both point and imaging spectroscopy in various domains (laboratory, field, and air and space). In addition, a significant progress had been established within the (big) data mining approach. This chapter provides a brief overview of the origin of this discipline along with a comprehensive presentation of its physical and chemical foundation. In addition, several core examples on how to use soil spectroscopy and obtain quantitative information are highlighted. Recent examples of how spectral information from the airborne domain is used for imaging spectroscopy (IS)/hyperspectral remote-sensing (HSR) domains is discussed. Special attention is thus given to the newly emerging imaging spectroscopy/hyperspectral remote-sensing technology from air and space domains and future notes are provided on the capacity of soil spectroscopy in real-time utilization. A comprehensive discussion emphasizes the importance of soil spectral libraries and global activity toward one master library is discussed, along with new approaches for data mining big spectral data. The benefits, limitations, and risks of soil spectral technology as well as hyperspectral remote sensing of soils from all domains are comprehensively discussed.