Presenting Magazine's Best On Decorating The ``house Beautiful Great Style'' Books Collect Useful Ideas.

What makes a room inviting? The appearance of ease, not effort. Chairs seem to have ambled into comfortable spots, pictures gravitated into their own constellations. Even objects on a mantel may have an unstudied air.

These are the rooms of House Beautiful: not just the magazine, which turned 100 last year, but the seven books that make up the House Beautiful Great Style series.

Why buy the books if you can read the magazine? Because the photographs, which were gorgeous the first time around, are repackaged here as mini-seminars on design. Their captions have been stocked with trade secrets, from the perfect shade of white (``Benjamin Moore's Number 1009, a translucent face-powder color'') to the fact that one designer's ballgown-style slipcovers are made from humble curtain-lining fabric.

Such are the decorating details that mortals, unlike designers, tend to overlook or flub, so it is a pleasure to see them up-close and analyzed. Choosing among these books (all from Hearst) is like pondering the dessert cart in a French restaurant. Here are mini-reviews of each, with samplings of insider advice:

* House Beautiful Details ($25), by the editors of House Beautiful, with text by Sally Clark. Forget clutter: This exquisite-looking book is about editing down, then playing up, your belongings in arrangements that look intriguing but not contrived.

Best tip: ``A lot of anything is always interesting to look at - especially when the individual items are everyday objects,'' writes Clark. A lineup of green pears qualifies. So can a row of clay flowerpots, if displayed with a minimalist attitude.

* House Beautiful Paint ($22), with text by Rhoda Jaffin Murphy. A portfolio of rooms in which paint - meaning texture and pattern, not just color - mimics stone floors, creates a night sky on a ceiling, or implies woodwork where none exists.

Best tip: Boost a low ceiling by painting the walls a solid color, then continuing it up onto the ceiling for 18 inches. The walls appear higher, Murphy writes, ``while the ceiling seems to shrink in area and become less dominant.''

* House Beautiful Color ($25), with text by Sally Clark. Natural palettes, which should be evocative, appear curiously bland on these pages. Even when color runs strong, the photographs add up to something less passionate and cohesive than in the other books.