Positive and negative externalities lead free markets to divert from allocative efficiency. Chapter 5 presents the possible role that government could play in improving allocative effiency where market failure exists. Are there markets where the divergence from allocative efficiency should be left alone (gov't stay out)? Are there markets where the divergence is so great that gov't absolutely should interfere? Are there actions that gov't could take in any of the markets you talk about (above) that would facilitate a private solution