Contributions to Economic Analysis, 132: The Fix-Point Approach to Interdependent Systems focuses on the Fix-Point method for the estimation of interdependent systems, including the Algebraic Fix-Point, Parametric Fix-Point, and Parametric Fractional Fix-Point methods. The selection first ponders on the fix-point approach to interdependent systems, iterative algorithms for fix-point estimation, and GEID specification. Discussions focus on the GEID estimator, convergence to multiple parameter sets, design of iterative algorithms, and challenges of simultaneous equations systems. The text then takes a look at the Parametric Fix-Point (PFP) and the Algebraic Fix-Point (AFP) methods; estimation of real-world models by fix-point and other methods; and a search for asymptotically efficient estimators. Topics include autoregressive errors, estimation of the Klein-Goldberger model, estimation of a model of the Czechoslovak economy, and the Parametric Fractional Fix-Point (PFFP) and Parametric Recursive Fix-Point (PRFP) methods. The text elaborates on fix-point estimates of the structure of a model using different Y proxy starts; analysis of the nonlinear Klein-Goldberger model using fix-point estimation and other methods; and fix-point estimation in interdependent systems with specification errors. The selection is a vital reference for researchers interested in the Fix-Point method for the estimation of interdependent systems.