High-harmonic generation (HHG) from solids has emerged as a powerful probe of electronic structure and ultrafast dynamics in condensed matter systems. In this chapter, we review recent advances in solid-state HHG spectroscopy and control, with a focus on semiconductors and correlated materials. We discuss the theoretical foundations of HHG and summarize experimental approaches for extracting information from harmonic emission. HHG has been shown to be sensitive to a wide range of microscopic properties, including band structure, transition dipole moments, Berry phases, crystal symmetry, carrier populations, dephasing processes, and lattice dynamics. This sensitivity enables access to electronic and structural dynamics on femtosecond and attosecond timescales and has established HHG as a versatile spectroscopic tool. At the same time, the strong dependence of HHG on many coupled material and excitation parameters makes the emitted harmonics intrinsically difficult to associate with a single microscopic quantity. Rather than representing a limitation alone, this sensitivity also provides numerous pathways for control. We review how photoexcitation, multicolor driving fields, waveform engineering, and transient modification of material properties can be used to enhance, suppress, and shape harmonic emission. These developments position solid-state HHG not only as a spectroscopic technique, but also as a platform for programmable nonlinear optics with applications ranging from compact extreme-ultraviolet sources to super-resolution microscopy and ultrafast photonic devices.