I. INTRODUCTION  
II. DATA  
A. DES Y3 Data  
B. T17 Mock Catalog  
III. THREE-POINT SHEAR CORRELATIONS  
A. Theory Basics  
B. Estimating $\Gamma_{i}$ and $\left<M_{\mathbf{ap}}^{3}\right>$  
C. Covariance Matrix  
IV. MEASUREMENT RESULTS  
A. Non-tomographic 3pt Shear Signal  
B. Tomography  
V. ASSESSMENT OF SYSTEMATICS  
A. Estimator Uncertainties  
B. B-modes and Parity  
C. PSF Residuals  
D. Mean Shear and Other Observational Systematics  
VI. COMPARISON WITH PREVIOUS WORK  
VII. CONCLUSIONS AND OUTLOOK