This volume covers different aspects of recent theoretical and observational work on magnetic reconnection, a fundamental plasma-physical process by which energy stored in magnetic field is converted, often explosively, into heat and kinetic energy. This collection of papers from the fields of solar and space physics, astrophysics, and laboratory plasma physics is especially timely in view of NASA's upcoming Magnetospheric Multiscale mission, which will use Earth's magetosphere as a laboratory to test, through in-situ measurement of the plasma, energetic particles, and electric and magnetic fields, the various and sometimes competing models and theories of magnetic reconnection. This volume is aimed at researchers in solar physics, magnetospheric physics and plasma physics. Previously published in Space Science Reviews journal, Vol. 160/1-4, 2011.