Although numbers and empirical analysis now pervade many fields of law, most lawyers have few skills in presenting or interpreting data or quantitative arguments. This course develops those skills. Law 394 is a one-semester, four-unit course aimed at enabling students to understand how quantitative ideas and methods are used by courts and regulatory agencies, and how to identify quantitative issues, competently supervise experts who do the heavy lifting, and present results. The course covers significance testing and regression analysis in some depth, but along the way we also examine probability, sampling and survey methods, basic finance math, and Bayesian reasoning. We will also devote a good deal of time to evaluating empirical arguments, assessing when claims are plausible or not, and how to investigate them further. During the semester, students complete eight problem sets and three short (5-9 page) papers. This course satisfies the law school's SAW requirement. The final exam is optional. Prospective students wondering if they have sufficient background for the course, or seeking additional information, can contact Professor Sander and examine the syllabus or other course materials from recent incarnations of the course.