The Wendelstein 7-X Stellarator (W7-X) is the next step device in the stellarator line of IPP Garching and is presently under construction. A new daughter institute of IPP is being built at Greifswald, Germany, to house W7-X. The design of W7-X is based on physics 'first principles', which lead to an optimized 3-D magnetic field configuration. The optimization principles are outlined and discussed in the light of experimental results from the W7-AS Stellarator. The results from W7-AS, which is the predecessor of W7-X and a partly optimized modular stellarator, are presented and show the experimental basis for stellarator optimization. The W7-X parameters resulting from both the physics objectives and the optimization criteria are effective major and minor radii of R₀= 5.5 m and a= 0.53 m, respectively, with a strong geometric variation of the magnetic surfaces. The confining magnetic field configuration is generated by a modular set of twisted coils with a magnetic induction of B_max = 3.0 T. The experiment aimes at demonstrating the inherent steady state capabality of stellarators at reactor relevant plasma parameters und is consequently equipped with a superconducting coils system and a heating arsenal of 10 MW ECRH, 4.5 MW NBI and 2 MW ICRH in the first stage. The 3-D topography of the stellarator askes for a special divertor solution to provide heat removal from the plasma under steady state conditions and to decouple the vessel wall from the plasma. The status of the design and construction of W7-X including heating systems, peripheral systems, divertor and diagnostics is presented.