which arise from the non-spherical outflow of matter from the atmosphere of the giant star. Z Andromedae started an unusually long active phase in September 2000, brightening by several magnitudes multiple times over at least a decade. During the outbursts, irregular brightness variations (up to 0.065 magnitudes) were observed at timescales shorter than a day, interpreted as warping in the accretion disk. If models for this source are correct, it should enter a quiescent phase again in 2020. Spectrum Optical The spectrum of Z Andromedae has been recognised as extremely peculiar since the early 20th century. Early spectra during a bright period, showing only emission lines against a red continuum, were interpreted as a star embedded in dense nebulosity. As the star's brightness faded, the spectrum lost the high excitation "nebular" lines and developed absorption lines with P Cygni profiles. These spectra were readily identified as being due to a hot nova-like star with a cool companion. Emission lines identified included low ionization states of hydrogen and helium with high ionization states of oxygen and iron. The MK spectral classification is typical of a cool giant, for example M4.5. The exact spectral type has been shown to vary, for example between M5 in 1987 and M3.5 in 1989. Infrared observations gave a combination spectral type of M2III + B1eq. Here the luminosity class of III is for a normal giant star, and the peculiarity codes eq indicate emission lines with P Cygni profiles. Ultraviolet Z Andromedae shows also a strong ultraviolet emission, which follows the optical behaviour; absorption lines identified during the quiescent phase becomes emission lines during outbursts. Elements identified in this region of the spectrum are carbon, nitrogen, phosphorus and silicon in their ionized states. Radio The radio flux from Z Andromedae at the beginning of outbursts is lower than the usual quiescent level, and has a maximum after the optical one. After the outbursts, radio jets can be seen flowing out of this system, in a direction perpendicular to the orbital plane. X-ray Z Andromedae is much fainter in X-ray, and has not been detected when in the quiescent phase. During outbursts, X-ray emission comes from shock-heated plasma, where the kinetic energy of the outflowing material is converted in X-ray radiation. This emission "mimics" a blackbody radiation with a temperature different from the one of the white dwarf, but its real nature can be identified because it