Abstract： Light-matter interactions are the fundamental basis for many phenomena and processes in optical devices. Whispering-Gallery-Mode (WGM) optical resonators trap light in a manner similar to a phenomenon found in the gallery spaces of St. Paul’s Cathedral dome in London, where a single whisper (i.e., a sound wave) can be heard along the circular boundary of the architecture. Ultra-high-quality WGM optical micro-resonators provide unprecedented capability to trap light in a highly confined volume smaller than a strand of human hair; a light beam can travel around the boundary of a WGM resonator over 106 times, significantly enhancing light-matter interactions, creating the potential for a wealth of new scientific discoveries and technological breakthroughs difficult to achieve by other devices. They have shown a great promise for a variety of fields of science, spanning from optomechanics to communication, non-Hermitian physics, sensing and metrology. In this talk, I will report the recent research discoveries from my group in this exciting field. I will present a few cases demonstrating the great potentials of high-Q WGM microresonators and microlasers for both fundamental science and engineering applications. I will start with the discussion of ultra-high-Q microresonators and microlasers for ultra-sensitive detection of nanoscale objects. Afterwards, I will discuss our recent exploration of fundamental physics, such as parity-time symmetry (PT-symmetry) and light-matter interactions around exceptional points (EPs) in high-quality WGM resonators, which can be used to achieve a new generation of optical system enabling unconventional control of light flow. Examples including nonreciprocal light transmission, loss engineering in a lasing system, directional lasing emission, and EPs enhanced sensing, will be introduced. A non-Hermtian phonon laser tuned in the vicinity of EPs will be discussed briefly. In the end I will present a new generic and hand-held microresonator platform transformed from a table-top setup, which will help release the power of high-Q WGM resonator technologies. I will wrap up my talk with an overview of Photonics Research, a journal to promote and disseminate high-quality research in photonics and optics.