Multi-channel marketing allows retailers to reach customers through multiple sales channels. The document discusses various retail channels including internet, catalog, direct selling, television home shopping, and automated retailing. It also covers the benefits of using a multi-channel approach, such as overcoming limitations of individual channels, increasing customer satisfaction and loyalty, and gaining insights into customer shopping behavior. Some challenges of effective multi-channel retailing mentioned are providing an integrated shopping experience, managing different distribution needs and information systems, and reducing channel migration.