The first solar jet seen by human beings was observed as an Hα surge by the Mt.Wilson Observatory in the 1920s. As jets are neither as dazzling as solar flares, nor can they affect the terrestrial environment like coronal mass ejections (CME), they failed to attract much attention. However, recent progress has shown that jets are playing very important roles in solar magnetic field topology and evolution, interacting with solar magnetohydradynamics (MHD) waves (such as Alfvénic waves), and heating local corona and accelerating fast solar winds. They could also have a close relationship with extreme solar eruptions such as flares and CMEs. In this article, we will briefly introduce the theories and observations of solar jets, and then describe our recent study on a solar jet triggering a fast coronal mass ejection. Finally, we will summarize some key problems that need to be solved, and key points for future research.