Based on the observation that lift producing circulation is the result of divergent reflective flows circumventing planform edges, this research presents a comprehensive new theory for finite rectangular wing aerodynamics. First the study presents a new expression for potential lift, emphasizing geometrical effects that reduce circulation strengths and lifting capacity. Second, a novel "crossflow separation vortex normal force" is derived through the application of the longoverlooked Milne-Thompson "Vortex Impulse Theory." The vortex force turns out surprisingly to be a linear function of the angle of attack. An empirical non-linear pressure drag normal force relationship is also provided to complement the linear theories. Since crucial experimental evidence shows that potential lift is absent in narrow wing cases, it is excluded in that range and only provides restricted contributions in wider configurations. This unique three element lift theory is proven to provide consistent and accurate predictions for all geometry ranges.