This paper has changed considerably since the first draft was circulated in 2000. Some readers may be interested in results that only appear in earlier versions. These results did not make it into the final published version because of space constraints. The 2004 draft contains the most detailed results on the consumption function of the deterministic case (σ goes to 0). The 2011 draft contains the most detailed results on the general class of utility functions with wealth dependent, but bounded, relative risk version.