Estelle Basor is professor emeritus of mathematics at the California Polytechnic State University, and deputy director of the American Institute of Mathematics. Her areas of research are in operator theory and the theory of random matrices.Albrecht Böttcher is professor at TU Chemnitz. He is an author of several books and has edited a number of recent books in the Operator Theory series.Torsten Erhardt is a professor at the UC Santa Cruz. His research interests range from functional analysis over harmonic analysis and Wiener-Hopf factorization theory to complex analysis. Craig A. Tracy is emeritus distinguished professor at UC Davis. His fields of research include statistical physics, integrable systems, and probability theory.

• Part I Harold Widom’s Life, Work, and Last Paper.- Biography of Harold Widom.- Domain Walls in the Heisenberg-Ising Spin-1/2 Chain.- Harold Widom’s Contributions to the Spectral Theory and Asymptotics of Toeplitz Operators and Matrices.- Visualizations of Two Functions Emerging in Connection with Toeplitz Determinants.- Part II Personal Notes.- A Remarkable Advisor, Mentor, and Friend.- My Encounters with Harold Widom.- Memories of Harold Widom.- Personal Reflection on Harold Widom.- Part III Invited Contributions.- Loops in SU (2) and Factorization, II.- Openness of Regular Regimes of Complex Random Matrix Models.- Focusing Nonlocal Nonlinear Schrödinger Equation with Asymmetric Boundary Conditions: Large-Time Behavior.- Algebras of Commuting Differential Operators for Kernels of Airy Type.- A Random Walk on the Rado Graph.- Widom Factors and Szeg˝o–Widom Asymptotics, a Review.- Some Recent Progress on the Stationary Measure for the Open KPZ Equation.- Probability of Two Large Gaps in the Bulk and at the Edge of the Spectrum of Random Matrices.- Multiplicative Properties of Infinite Block Toeplitz and Hankel Matrices.- Toeplitz and Related Operators on Polyanalytic Fock Spaces.- Strong Szeg˝o Theorem on a Jordan Curve.- Toeplitz Operators with Non-trivial Kernels and Non-dense Ranges on Weak Hardy Spaces.- Rényi Entropies of the Free Fermi Gas in Multi-Dimensional Space at High Temperature.- Spectral Asymptotics for Toeplitz Matrices Having Certain Piecewise Continuous Symbols.- Global and Local Scaling Limits for Linear Eigenvalue Statistics of Jacobi β-Ensembles.- On the Limit of Some Variable-Coefficient Toeplitz-Like Determinants.- On Diagonalizable Quantum Weighted Hankel Matrices.- On the Product Formula for Toeplitz and Related Operators.