4U 2206+54, a multiwavelength approach

4U 2206+54, a High Mass X-Ray Binary (HMXRB) system discovered with UHURU data in 1972, was initially classified as a BeX system (with BD+53 degrees 2790 as the optical counterpart). After a long term monitoring campaign, the multiwavelength approach allowed us to unveil the real nature of this system. From Radio wavelengths to gamma-ray energies, we present a complete analysis of this system which includes the detemination of the nature of both, the optical and compact component, as well as the properties of the mass transfer mechanism and a constraint to the orbital parameters of 4U 2206+54. From optical data (from ground-based telescopes), the spectral type of the optical companion is derived. From infrared and IN observations (from on ground telescopes and IUE respectively), the nature of the expanding envelope of BD+53 degrees 2790 is analysed. From a combination of Radio and High energy observations (from NRAO/VLA, INTEGRAL and RXTE), the nature of the compact companion is derived. By combination of the timing analysis from high energy light curves, and optical spectroscopy, the orbital parameters of the system can be constrained.