The elliptic sine-Gordon equation is the nonlinear PDE q x x + q yy = sin q, q = q(x, y), x, y ∈ .( 5 . 1 ) This equation appears as a mathematical model of several physical phenomena. For example, it was derived in the context of the theory of Josephson effects, superconductors, and spin waves in ferromagnets; see [35]. From a strictly mathematical point of view, the elliptic sine-Gordon equation is the simplest and most fundamental example of an nonlinear elliptic integrable PDE, in the sense of admitting a Lax pair formulation. Therefore the tools developed in connection with the so-called inverse scattering transform can be used for its analysis, at least in principle. The fundamental problems with using inverse scattering approach is that the problems posed for this PDE are always boundary value problems, and hence one has to turn instead to the unified transform approach, introduced by Fokas in the late 1990s.The inverse scattering analysis for this integrable equation had been considered in [7] for a problem posed on 2 with prescribed periodic behavior at infinity, and in [35] for the problem on a half plane y ≥ 0, with all boundary values prescribed, but constrained by a certain nonlinear relation. Due to the limitations of the inverse scattering approach when dealing with boundary value problems, in these works the solution is not constructed effectively. Special exact solutions for the problem posed in the whole of 2 were found in the 1980s by various authors (see the references in [35]).Recent progress was made using the unified transform [43,45,29,30]. In this series of works, the equation was considered on a half plane, quarter plane, and semistrip. Particular cases of boundary conditions that yield an explicit representation for the solution were identified and analyzed. In this paper, we summarize this recent progress to