A scintillating crystal detector offers potential advantages in low-energy (keV-MeV range) low-background experiments for particle physics and astrophysics. The merits are discussed using CsI(T1) crystal as illustrations. The various physics topics, which can be pursued with this detector technology, are summarized. A conceptual design for a generic detector is presented. (C) 2000 Elsevier Science B.V. All rights reserved.