WOMEN UNDER 30 may wonder why Bess Truman, who died in Kansas City, Mo., this week at the age of 97, was an object of such affection and respect for those with a memory of post- war America. Surely she was not a political power in her own right, like Eleanor Roosevelt, nor glamorous and exciting, like Jacqueline Kennedy. She had no causes of her own, no prot,eg,es, no press conferences. Her husband said she looked "just the way a woman who has been married 25 years should look," and she described the role of first lady as requiring that a wife "sit beside her husband, be silent and be sure her hat is on straight." Why, then, was she so special to us?

In the years immediately following the turbulence of Depression and world war, Americans found reassurance and inspiration in the virtues Mrs. Truman personified. She was from the heartland and appeared to cherish all the good values of small-town America that we like to believe are universal in this country. She was warm, modest, friendly and home- loving. Her family came first, and that feeling was reciprocated by her husband and daughter. There is something touching about childhood sweethearts who marry, have a family, live in a white clapboard house and are still holding hands and enjoying private jokes on their 50th wedding anniversary. If President Truman held a personal grudge against anyone -- public figure or private citizen -- who had anything bad to say about his "girl," as he called his wife, we think better of him for it, and envy her.

Mrs. Truman had a sense of duty, dignity and quiet pride, and a sense of proportion. She was correct and gracious about everything she did in the White House, and she served the country and her husband well. When it was all over, she was delighted to return to Independence, to her friends and to privacy. Within hours of leaving office, she was telling the former president to "go up into the attic and put away the suitcases."

In each of our families there is a woman who looks rather like Bess Truman and who embodies these same down-to-earth virtues. She reminds us of someone we love -- a mother, a teacher, a favorite aunt. We mourn her not so much as a public figure but for what we knew of her private role as a wife, mother and model for so many women of her generation.