Associate, Emeritus, Fellow, Honorary, Member, Retired, Student, or Sustaining. The more contact between the two groups the better, of course.
Sections vary greatly in size and in level of activity.
While far from complete, and still lacking in many areas such as a good discussion of the adverse effects of poor lighting and what to do about them it is an invaluable resource. Part II, Lighting Engineering, includes Light Sources, Luminaires, Daylighting, and Lighting Calculations. Part III, Elements of Design, includes Lighting Design Process, Illuminance Selection, Basic Lighting Calculations, Lighting Economics, and Codes and Standards. There is also a Glossary of Lighting Terminology and several appendices. Individuals also give seminars, though these are often more expensive.