Editorial Introduction -- Part 1: Biographical Material and List of Publications of L.A. Sakhnovich -- L.A. Sakhnovich – Biography -- List of Publications of L.A. Sakhnovich -- L.A. Sakhnovich My Teachers and Studies -- Part 2: Reserach Papers -- D. Alpay, F. Colombo and I. Sabadini: Inner Product Spaces and Krein Spaces in the Quaternionic Setting -- D. Alpay, P. Jorgensen, I. Lewkowicz and I. Martziano: Infinite Product Representations for Kernels and Iterations of Functions -- Y. Arlinski˘ı and S. Hassi: Q-functions and Boundary Triplets of Nonnegative Operators -- S. Boiko, V. Dubovoy and A. Kheifets: On Some Special Cases of the Radon–Nikodym Theorem for Vector- and Operator-valued Measures -- A.E. Frazho, S. ter Horst and M.A. Kaashoek: State Space Formulas for a Suboptimal Rational Leech Problem II: Parametrization of All Solutions -- B. Fritzsche, B. Kirstein and C. Mädler: On a Simultaneous Approach to the Even and Odd Truncated Matricial Hamburger Moment Problems -- F. Gesztesy and R. Nichols: A Jost–Pais-type Reduction of (Modified) Fredholm Determinants for Semi-separable Operators in Infinite Dimensions -- K.A. Makarov and E. Tsekanovski˘i: On the Addition and Multiplication Theorems -- J. Rovnyak and L.A. Sakhnovich: On Indefinite Cases of Operator Identities Which Arise in Interpolation Theory. II -- A. Sakhnovich and L. Sakhnovich: Nonlinear Fokker–Planck Equation: Stability, Distance and the Correspond ing Extremal Problem in the Spatially Inhomogeneous Case.