A Juris Doctor degree, or J.D. is the first graduate law degree a person can attain. It requires a student to go through three years of education which covers general topics such as tort, civil procedure and evidence. Some J.D. programs allow students to specialize in specific areas of law, such as business law or environmental law. There are also a number of elective courses that can be chosen. The J.D. is the most basic degree that allows a person to practice law in the U.S.
Although its name may indicate otherwise, the Master of Law, or LL.M. is actually the second degree attainable in law (master degrees are usually the first graduate degrees attainable). An LL.M. student must have already received a J.D. The LL.M. allows a student to specialize in a particular area of law such as environmental law, tax law or technology law. The areas of law available for an LL.M. degree are numerous and depend on the LL.M. program.
The Doctor of Juridical Science (S.J.D.) is the highest law degree attainable in the U.S. and requires a student to have already attained a J.D. and an LL.M. This program is another three years and is research intensive. Unlike the other two programs, the S.J.D. is tailored to the research topic of the student. The vast majority of work in a S.J.D. program will involve research and writing a dissertation paper.
Some law schools have combination programs that combine a J.D. with another graduate degree in another field. For example, it is not uncommon for law schools to offer a J.D.-M.B.A. program where law students split their time between law school and business school. It is also possible for a law degree to be combined with master's degrees in environmental or race studies. These programs are usually referred to as dual-degree or joint-degree programs.