The document discusses the complex structure of the US federal tax law, which results from competing objectives in developing tax policy. It outlines various economic, social, equity and political considerations that influence tax law. It also describes the key agencies and sources of tax law, including the Internal Revenue Code, Treasury regulations, revenue rulings, judicial precedents and more. Finally, it discusses tax research and the process of identifying, assessing and applying relevant tax law authorities to arrive at solutions to tax issues.