This document discusses how companies can build and manage their product mix and product lines. It defines product mix as the set of all products a company offers for sale, and product lines as sets of related products made by the same company. It discusses factors like the width, depth, and consistency of product lines. It also covers analyzing product line contributions, market profiles, competition, and deciding on product line length and mix through tools like product maps. Finally, it discusses optimizing brand portfolios through modernization, selective featuring, and rational pruning.