Many research teams have developed various innovations in the field of assistive robotic exoskeletons for the lower limbs. Especially in the recent years, because of the expeditious technological development, much work has been done and published in the scientific communities. However, in the publications, for different reasons and constraints, the information available is in bits and pieces. Most papers only could manage to speak of the individual aspects like the mechanical design or state machine or interface or another control scenario, etc. This is why an attempt of bringing all together and digging deep into all the scientific aspects was made at the best. This is achieved by comparing and analysing the most popular and various kinds of exoskeletons. Therefore, in this chapter a complete walkthrough the mechanical design, electrical control, software interface, material selection and simultaneously applied algorithms were discussed. Coming to numerical and analytical simulations like forward and inverse kinematics, dynamic simulation of the moments of the multibody systems, etc., were performed in MATLAB and OpenSim simulation platforms. Better solutions were proposed and awaiting challenges were discussed for each aspect of the robotic exoskeleton.