Abstract
An introductory survey of quasicrystals is presented. Some experimental observations that seem typical of nonperiodic long-range order are reviewed critically. The atomic structure and crystallography are described within the framework of the strip-projection formalism, with special attention to the consequences for diffraction approaches and the event of a new kind of crystallography. Atomic decoration models are presented briefly and discussed in the light of experimental data. A few physical properties are also mentioned, or rather it is suggested what they might be.