Current nuclear reactors are very complex, inefficient, and expensive. The Dual Fluid Reactor (DFR) concept, addresses these problems. The DFR is a compact high temperature fast reactor, that is cheaper to build and operate, highly efficient, and inherently safe. DFR is essentially a heterogeneous molten salt fast reactor with a liquid coolant and a liquid fuel whereby both circulate through the reactor core. Unlike the MSRE (Molten Salt Reactor Experiment, Oak Ridge 1964-1969) and all Generation IV MSFR (Molten Salt Fast Reactor), the disentangling of the cooling and fuel supply functions has many advantageous properties in comparison to the MSFR, where both functions must be satisfied by one material in a compromise. In the MSFR, the material is essentially restricted to molten salt which is a trade-off between high-temperature fuel, low-temperature cooling, and acceptable heat capacity. The DFR concept will be described in detail, including choices of fuels, coolant, core materials, inherent safety features, preliminary economics, and various applications. Furthermore, detailed comparison between DFR design concept and those of current GIII, GIII+, and GIV reactors will be presented in terms of safety, cost, and proliferation resistance.