The PARASOL Interface is an application and solver-independent software layer that allows the efficient co-operation of industrial finite-element codes and advanced parallel solvers developed within the PARASOL project. The PARASOL Interface is complemented by the extended Rutherford-Boeing File Formats for the external representation of the matrix-based and finite-element problems. The PARASOL library includes a prototype implementation of the PARASOL interface for the PARASOL solvers and external solvers like PSPASES and WSSMP. Within PARASOL, new parallel algorithms have been developed for the direct solution of sparse systems of linear equations, for the iterative solution of such systems based either on multi-grid or domain decompositioning and for their preconditioning. These algorithms are implemented as portable prototypes and are integrated into the PARASOL library. The corresponding PARASOL interface is specified in analogy to the MAxx codes of the sequential Harwell library and is publicly available. Application of the PARASOL results takes place in various areas, mainly mechanical engineering, structural analysis, flow simulation, extrusion and chemical simulation. During the project, input data was provided from software packages like MSC.NASTRAN, Polyflow, SESAM. Examples are crankshaft segments of combustion engines, car bodies, ship hulls or liquid flows within mixing tanks. All these are applications of high importance to industry and they have been analysed with parallel solver technology to provide results within a shorter time or for larger models than today's technology can efficiently handle.