Neutron scattering is an important experimental technique in amongst others solid state physics, biophysics, and engineering. This year construction of European Spallation Source (ESS) was commenced in Lund, Sweeden. The facility will use a new long pulsed source principle to obtain higher potential performance than any existing facility, however in order to use this pulse structure optimally many existing neutron scattering instruments will need to be redesigned. This defense will concentrate on the design and optimization of the inverse time-of-flight cold neutron spectrometer CAMEA. The instrument is ideally suited for solid state experiments with extreme sample environments such as large pressures and strong magnetic fields. CAMEA combines the time-of-flight technique to determine the energy of the incoming neutrons with a complex multiplex backend that will analyse and detect an unprecedented large fraction of neutrons scattered in the horizontal plane. Together with the ESS source this will produce an instrument that promises several orders of magnitude higher performance than the best currently existing neutron spectrometers. The design of CAMEA involved kinematic calculations, simulations and prototyping to optimize the instrument and ensure that it will deliver the predicted performance when constructed. During the design a new prismatic analyser concept that can be of interest to many other neutron spectrometers was developed. The design work was compiled into an instrument proposal for the European Spallation Source, and approved for construction. CAMEA will thus be constructed in Copenhagen as a Swiss-Danish contribution to ESS.