If you have to live and work in a two-room apartment, you can do so with remarkable efficiency and also retain a sense of serenity and order. That's the theory of interior designer Lloyd Bell. Mr. Bell knows whereof he speaks. For years he lived here in a spacious uptown brownstone, where he acquired a multitude of antiques, paintings, books, and other objects. He then moved to a 4,000-square-foot Chelsea-area loft, where he had even more space to put more things.
Then one day he decided to move into the 850-square-foot East Side apartment that he had used solely for his professional design practice. ''I faced up to a difficult decision, which meant not only divesting myself of most of my worldly goods and making do with less, but then trying to work at home with a minimum of clutter and disruption of my normal living pattern,'' Mr. Bell says.
He took the plunge, and decided if he was going to streamline and simplify his life, he had to reduce his possessions drastically. Within a short time he had disposed of everything but two chairs, 18 favorite paintings, and a small cluster of treasured objects. He then began to rethink and replan his small apartment so that he would have everything he absolutely needed, but nothing more.
He decided on the kind of financial investment in the project that would convert his shrunken living quarters into a suitable work-living environment and a showcase that would illustrate to clients how limited space could be used to the maximum.
Here are highlights of his confrontation with the problem, along with some of his reflections:
* Sufficient storage is the key to success in living in a small area. Without adequate storage your life can have no order, and without order, you live in a perpetual mess. So you must plan a place for everything you own, and then discipline yourself to keep things in those places. It took the designer a while to learn that shipshape meant exactly that, but now he removes a book for every new one that he brings home.
* With minor adjustments, Mr. Bell reworked several closets to get double-depths, and he used all recesses between building beams in either functional or decorative ways. He made a major investment in built-in shelves, drawers, and cupboards in each room, and had standard office equipment - filing systems, drawers, and work counters - installed in the small office he created by walling off half the bedroom space.
* Thus, this important suggestion for living in such circumstance: Provide a separate workplace where you can leave things out and on which, if possible, you can close the door. Mr. Bell not only carved out an office, but also created a small, out-of-sight drafting room off the kitchen. If, he says, you don't have the budget to wall off such work areas, do it with folding screens or ceiling-to-floor slat blinds, which are relatively inexpensive, but do the job.
* Since Mr. Bell wanted to work and see clients in an attractive living room that in no way resembled an office, he devised a large, round, glass-top table that would fit into a rectangular red-lacquer plinth. The plinth is a clever camouflage, for it houses, on slide-out trays or drawers, telephone, supplies, and immediate files for day-to-day business. Its lighted top is decorated with a large blue Chinese ceramic pot filled with tall fronds. The table also doubles for conference use and for dining or buffet serving.
* When working with small spaces, be very conservative with color, and fairly monochromatic. Mr. Bell chose a warm, milky-caramel reflective glaze for all walls, ceilings, and woodwork. Kitchen cabinets and appliances were finished in the same color.
* Be sparing of lamps. Mr. Bell, who is a fellow of the American Society of Interior Designers, has made a real design feature out of the matte-black metal-track lighting used on all ceilings. He also uses concealed up-light to illuminate works of art displayed on glass shelves.
* Use mirrors in unusual ways. Mr. Bell has mirrored the sliding panels that close off his bedroom windows, the recessed niche on the facing wall of his entry hall, and the recessed glass shelves for displaying decorative treasures.
* Establishing logical traffic patterns in rooms is essential, and furniture must be arranged to provide easy movement of people. The scale and proportions of new-furniture purchases must take such traffic patterns into consideration.
Having established his new work-living order, Mr. Bell says of his more contained life style, ''I guess the chief satisfaction involved in a move like this is the discovery that you don't really need all those things.''