These are the refereed post-proceedings of the Third International Conference on Large-Scale Scientific Computing, LSSC 2001, held in Sozopol, Bulgaria, in June 2001. The papers are organized in topical sections.

Invited Papers.- Optimizing Two-Level Preconditionings for the Conjugate Gradient Method.- On the Parallelization of the Sparse Grid Approach for Data Mining.- Java Communications for Large-Scale Parallel Computing.- Continuous Path Brownian Trajectories for Diffusion Monte Carlo via First- and Last-Passage Distributions.- Multilevel Monte Carlo Methods.- Iterative Aggregation/Disaggregation Methods for Computing Some Characteristics of Markov Chains.- Time-Integration Algorithms for the Computer Treatment of the Horizontal Advection in Air Pollution Models.- Robust Preconditioning Algorithms.- MIC(0) Preconditioning of Rotated Trilinear FEM Elliptic Systems.- Sobolev Space Preconditioning for Mixed Nonlinear Elliptic Boundary Value Problems.- On a Schur Complement Approach for Solving Two-Level Finite Element Systems.- Monte Carlo Methods.- On-Line State Estimation of Maneuvering Objects by Sequential Monte Carlo Algorithm.- On the Dyadic Diaphony of the Sobol‘ Sequences.- An Improved Monte Carlo Algorithm for Elastic Electron Backscattering from Surfaces.- Statistical Algorithms for Simulation of Electron Quantum Kinetics in Semiconductors - Part I.- A Quasi-Monte Carlo Method for Integration with Improved Convergence.- Solving Systems of Linear Algebraic Equations Using Quasirandom Numbers.- Monte Carlo Analysis of the Small-Signal Response of Charge Carriers.- Statistical Algorithms for Simulation of Electron Quantum Kinetics in Semiconductors - Part II.- Advanced Programming Environments for Scientific Computations.- IC2D: Interactive Control and Debugging of Distribution.- JaMake: A Java Compiler Environment.- Program Development Environment for OpenMP Programs on ccNUMA Architectures.- Global Computing Systems.- Java for Large-Scale Scientific Computations?.-Java for Scientific Computation: Prospects and Problems.- Large-Scale Computations in Air Pollution Modelling.- Object-Oriented Framework for Large Scale air Pollution Modeling.- Evaluation and Reliability of Meso-Scale Air Pollution Simulations.- The Mathemathical Background of Operator Splitting and the Effect of Non-Commutativity.- Fine-Grid Resolution in Danish Eulerian Model and an Implementation on SGI Origin 2000 Computer.- Modelling Framework for Atmospheric Mercury over the Mediterranean Region: Model Development and Applications.- Iterative Load Balancing Schemes for Air Pollution Models.- Computational Aspects of Air Quality Modelling in Urban Regions Using an Optimal Resolution Approach (AURORA).- Parallel Implementation of a Large-Scale 3-D Air Pollution Model.- Long-Term Estimates of Sulfur Deposition in the Region of Southeastern Europe.- Computationally Efficient Atmospheric Chemical Kinetic Modeling by Means of High Dimensional Model Representation (HDMR).- Large-Scale Computations for Mechanical Engineering Problems.- Computer Simulation of the Air Flow and the Distribution of Combustion Generated Pollutants around Buildings.- On Multigrid Methods for the Compressible Navier-Stokes Equations.- Structural Optimization of Biomorphic Microcellular Ceramics by Homogenization Approach.- Multigrid - Adaptive Local Refinement Solver for Incompressible Flows.- Handling Systems from Non-linear Theory of Elasticity.- Numerical Modelling of the Flow in Magnetic Liquid Seals.- Dynamic Mesh Schemes for Fluid-Structure Interaction.- Numerical Methods fpr Incompressible Flow.- Boundary Integral Method for 3D Simulation of Foam Dynamics.- A Lagrange Multipliers/Fictitious Domain Approach for Particulate Flow.- Primal vs. Dual Variable Approach for Mixed-Hybrid FiniteElement Approximation of the Potential Fluid Flow Problem in Porous Media.- Wave Evolution of Heated Falling Films. Numerical Analysis Using Finite-Difference Method.- Picard-Uzawa Schemes: Errors, Convergence and Stopping Criterion.- Contributed Papers.- Finite Element Method for Plates with Dynamic Loads.- MPI Parallel Implementation of a Fast Separable Solver.- A Comparison of Subspace Methods for Sylvester Equations.- Studying the Performance Nonlinear Systems Solvers Applied to the Random Vibration Test.- Parameter Identification in a Two-Dimensional Parabolic Equation Using an ADI Based Solver.- Numerical Simulation of a Model for Transport and Reaction of Radionuclides.