TFhe last few years have seen a resurgence of interest in the old question of how best to raise tax revenue. Roughly speaking, two different problems have been studied. TFhe first is to find a set of commodity taxes that is optimal given certain efficiency and (sometimes) equity considerations. In a second strain of the literature, it is assumed that the revenue system is based upon income rather than commodity taxation, and the problem is to determine the optimal degree of progressivity (or regressivity) .1,2 TI he principal motivation of some writers in the optimal taxation literature seems to be the discovery of fairly simple rules which policy makers actually can implement. Others are more interested in theoretical exploration of the implications of alternative economic assumptions than in developing usable policy recommendations. Practically all the contributions, however, have been quite mathematical and thus inaccessible to many practitioners in the public finance area. The purpose of this essay is to discuss in a nontechnical way the methodology and principal conclusions of the optimal taxation literature.3 In Sections 1 and II are discussed the optimal commodity and income tax literatures, respectively. Following this are some observations on the accomplishments of optimal taxation research and on some open questions.

We investigate the effect of entrepreneurs' personal taxes on their use of labor, analyze the tax returns of sole proprietors before and after the Tax Reform Act of 1986, and determine how the substantial reductions in marginal tax rates affected their hiring decisions and wage bills. Individual income taxes exert a statistically and quantitatively significant influence on the probability of hiring workers. Raising the entrepreneur's “tax price” by 10% raises the mean probability of hiring by about 12%. Further, taxes influence total wage payments to workers. The tax‐price elasticity of the median wage bill is about .37.

We develop a technique to assess the impact of changes in mortgage markets on households, exploiting an implication of the permanent income hypothesis: The higher a household's expected future income, the higher its desired consumption, ceteris paribus. With perfect credit markets, desired consumption matches actual consumption and current spending forecasts future income. Because credit market imperfections mute this effect, the extent to which house spending predicts future income measures the “imperfectness” of mortgage markets. Using micro‐data, we find that since the early 1980s, mortgage markets have become less imperfect in this sense, and securitization has played an important role.