By Martha Bashers and Margery Passett. $3.75 at bookstores or from MMK Associates, 5441 33rd St. NW, Washington, D.C. 20015 (include twently-five cents for handling).

For you, summer may not have started; but for summer camps, the summer began about six months ago, when they began filling their rosters. So what do you do now that warm weather has reminded you that the children will be out of school for three months? You turn, in desperation, to the new edition of Summer Programs for Children in the Washington, D.C., Area.It lists all the day camps, their fees, programs, ages and such. But you are too late for many of them. There may still be time for the tennis clinics, basketball camps, and swimming classes it lists. The dance, theater, music and arts programs are iffy. But you could look into the volunteer programs and the field trips. And, if all else fails, there is still a complete list of public swimming pools and tennis courts. And now is the time to start looking into day camps for next year, to see them in action before you have to make your decision next winter. Summer Programs for Children in the Washington, D.C., Area.