Gilliatt is a British-born interior designer who has written more than two dozen decorating books. Her latest, published by Little, Brown ($21.95), is a companion to the series. She specializes in making the arcane accessible, and much of the series concentrates on a visual dictionary, with definitions of various styles and design elements. With her British accent and her conservative cardigans and pearls, Gilliatt comes across like a proper nanny, offering instruction on decor rather than decorum. As might be expected, she favors a modified English country look, with an emphasis on flowered chintzes, comfortable seating and traditional furniture styles.

The first episodes alternate between a studio living-room set, which progresses from banal to budget-conscious to baroque, and a real live ugly-duckling house, which turns into a well-coordinated swan under Gilliatt’s direction. Gilliatt uses the set to teach the basics: how to arrange a room to get maximum seating, how to make the most out of awkward corners, how to use color to set a mood. The house in progress shows how to apply these basics. Along the way, Gilliatt gets help from a handful of experts in such specialties as faux finishes, window treatments (lots of swags and pelmets here) and decorative floor painting. The experts are generally the weakest part of the show; the average do-it-yourselfer isn’t likely to take on many of the projects they demonstrate. In one show, a floor painter turns plain wood into a garish red-and-blue checkerboard pattern. The only sane response: don’t try this at home.

Like “This Old House,” the show is slow in the beginning, but, after a while, it grows on you. Watching the chameleonlike studio set turn from high Victorian (deep red and green walls, faux marble fireplace, huge potted palm) to Gilliatt’s version of neoclassical is a little like watching a soap opera unfold. What will happen to that ugly little corner when a new desk is brought in? Will the love seat adjust to more formal upholstery? Will the chair rail still show up with black and white striped wallpaper? Stay tuned.

Faithful readers of HG or House Beautiful will learn nothing new. In fact, there’s a decidedly middlebrow quality to the show. Everything matches; the blue and red flowered wallpaper and comforter in the bedroom, for example, are from-surprise!–Gilliatt’s own design line and were, literally, made for each other. It’s a safe and reasonably pleasant way to do a room, but not very exciting or personal.

However, like model rooms in decorator show houses, Gilliatt’s rooms do provide tips that you can take home. In the living room, she designed clever built-in storage under and around windows. She likes window seats because they give extra seating-useful for parties-without taking up a lot of floor space. In a child’s room, chests from an unpainted furniture store and a long wood counter form an inexpensive work-and-storage space. The kitchen is dramatically transformed with a few simple tricks. Fresh white paint on the cabinets, tiles on the counters and backsplashes and wallpaper give the room bright new life. They’re basically cosmetic, as opposed to structural, changes-and they won’t break the bank. As Gilliatt says, “Having more dash than cash never hurt anyone.” Throw in a pelmet or two, and you’ve got a room.