This work deals with two main decision problems which arise when flow-line production systems are installed and operated. The assembly line balancing problem consists of partitioning the work necessary to assemble the product(s) among different stations of an assembly line. If several models of a product are jointly processed on a line, this medium-term problem is connected wih the short-term problem of determining an operating sequence of the models. In part one, balancing and sequencing problems are discussed, classified and arranged within a hierarcdhical planning system. Part two is concerned with exact and heuristic procedures for solving those decision problems.