Timothy Lonergan, age 11, of Staten Island, N.Y., for his question:

WHAT IS A PH.D. DEGREE?

The most important research doctor's degree that can be obtained through university study is the Doctor of Philosophy, abbreviated as Ph.D. To obtain this high degree a person must first obtain a master's degree and then take an additional two or three years of research and study.

To earn a Ph.D. degree a candidate must complete a long series of examinations and also present an original contribution to knowledge in the form of a thesis as well as a more detailed study of a research problem than that required for the master's degree.

Most doctoral students are expected to have a reading knowledge in two foreign languages as well as a broad field of knowledge and a mastery of scholarly research techniques.