DEAR ABBY: I am a 14-year-old girl with a big problem. My family consists of my mother, father, older brother, "Jared" (age 19), and younger brother, "Jonas" (age 11). So what's the problem? I have just learned there was another brother!

About a month ago, when my family was sitting down at dinner, we were talking about birth statistics. Out of nowhere, Jonas said, "A lot of infants die." My parents exchanged sad looks across the table, and my mom cried in her bedroom afterward.

I was so confused by this that Jared talked to me privately and told me. Apparently, Jonas was one of a set of twin boys. Jonas' twin was born prematurely and died. I believe Jared because he was 8 at the time and witnessed the whole thing. I doubt he would joke about something like this.

I think it's my right to know more about my third brother. I feel guilty that I don't even know his name. I have been keeping this knowledge a secret for more than a month now, and it's making me crazy. Should I ask my parents about him even though it will make them cry?

"" BROTHER-DEPRIVED IN ROCHESTER, N.Y.

DEAR BROTHER-DEPRIVED: Of course it is your right to know about your third brother. However, let me caution you to proceed very gently. Obviously your mother's heart was broken, and this is something from which she may never completely recover. There also might not be much to tell &

other than how devastating the loss was to her and your father.

DEAR ABBY: I'm a 32-year-old female who has been having an affair during the last year with my 59-year-old married boss. I am madly in love with him and divorced my husband eight months ago to marry him.

He promised to divorce his wife, but so far there is no sign of divorce. I'm beginning to think I'm a big fool. What do you think?

"" HOT TO TROT IN BIRMINGHAM, ALA.

DEAR HOT TO TROT: I agree.

DEAR ABBY: I work in a library and have noticed an alarming trend. People are using their mail as bookmarks, often forgetting that it is there and returning the books. I can't tell you how many times I have found people's personal information in books that I reshelve.

Abby, please alert your readers that this practice of using mail to mark your library book is unsafe in this age of identity theft. If I don't find it first, anyone who takes the book after you and finds something you might have left there will have immediate access to your name and address. And if the mail is something sensitive, like a bill or bank statement, the dangers are even greater.

Please remind your readers that it's easy to forget, and mail is not an appropriate bookmark.

"" JON IN FRAMINGHAM, MASS.

DEAR JON: Thank you for writing. I am printing your letter as a public service announcement. Readers, if you are guilty of this practice, be warned.

Dear Abby is written by , also known as Jeanne Phillips, and was founded by her mother, Pauline Phillips. Write Dear Abby at or P.O. Box 69440, Los Angeles, CA 90069.