Introduction

The Submillimeter Array (SMA) has made numerous and important contributions to extragalactic research. Such observations require the highest sensitivity and stability from the SMA. Since its inception, 39 papers (19%) have been published in extragalactic astronomy, resulting in 304 citations. Topics investigated include: (1) the discovery of high-redshift (z > 3) submillimeter galaxies and estimates of their stellar mass and sizes; (2) high resolution images of the distribution of gas and dust and the motion of gases in the cores of infrared luminous and ultraluminous galaxies, (3) new insights into the central structure of blazers, QSOs, and high-redshift radio galaxies, (4) observation of an extragalactic H₂0 maser at submillimeter wavelengths, (5) search for structure in a Lyman α blob, (6) and use of the extended SMA (eSMA; SMA, JCMT, and CSO) for the first detection of [C I] in a quasar. This section highlights all extragalactic research carried out with the SMA, except studies of nearby galaxies. As the SMA continues to improve in sensitivity, stability and ease of operation, its ability to observe extragalactic sources will continue to improve significantly.