This report assesses the impact of mandatory minimum penalties on federal sentencing, particularly in light of the Supreme Court's decision in Booker v. United States, which rendered the federal sentencing guidelines advisory. The United States Sentencing Commission prepared this report pursuant to a congressional directive contained in section 4713 of the Matthew Shepard and James Byrd, Jr. Hate Crimes Prevention Act of 2009, Pub L. No. 111–84, and the Commission's general authority under 28 U.S.C. §§ 994–995, as well as its specific authority under 28 U.S.C. § 995(a)(20) to "make recommendations to Congress concerning modification or enactment of statutes relating to sentencing, penal, and correctional matters that the Commission finds to be necessary and advisable to carry out an effective, humane, and rational sentencing policy."