Dear Lee,

Years ago we went on a trip and, for safety’s sake, I hid our silver tea set in boxes buried among our collection of old advertising. The tea set was safe from burglars, but by the time we got home I forgot where I hid it and the tea set wasn’t uncovered for months.

Collectors hide things for many reasons. A New York Times review of Family Secrets, a new book by history professor Deborah Cohen, considers theories about the who, where and why of “the hiding habit.” It seems to be a common human trait.

We all need our own personal space and our own secrets. My aunt was an extravagant collector and her husband considered collecting a bad habit. She went to estate sales and bought antiques, then hid them in the attic. A few years later, she would rescue an ivory carving or vase from the attic and put it on a table in the living room. When my uncle noticed it, she could give an honest answer: “Oh, that has been in the house for years.” She avoided arguments and could continue to follow her passion for collecting.

Remember the human penchant for hiding things when you’re selling a house or settling an estate. Old houses often have built-in shoe-rack cupboards inside closets. They were made to store out-of-season shoes. At one house sale, we opened the wooden compartment and found paper dolls, carved wooden animals (a monkey, elephant and lion) made in Denmark, and a child’s diary—all hidden away by a little girl in the 1960s. Her private space remained a secret for years. Today the wooden monkey alone sells for $200.

So use your imagination if you’re involved in downsizing your own home or distributing an estate. Real jewelry is often hidden in a box of costume jewelry. Important papers, even money, can be hidden between the pages of a book. Look behind the dust panel on the back of every picture, inside the hem of drapes and in kitchen boxes and bins. A man we knew hid small valuables in a bag he taped inside his laundry chute.

Check under each drawer in a dresser; something may be taped to the bottom. Climb up and check the back of high shelves and look under mattresses and inside pillowcases. An elderly neighbor sewed her diamond bracelet into a decorative pillow to keep the heirloom safe for her daughter. She explained the bequest in her will, but an estate sale was held before the will was read and the pillow had been sold.

We are all programmed to hide valued things—and collectors have more to hide than most. Decide if it’s best to display everything in your collection or to keep some things stored in secret hiding places. But don’t let the secrets die when you do—tell someone in your family or a close friend where to look.