It has: 12 bedrooms, 37 bathrooms, four dining rooms, six kitchens, 10 fireplaces, 137 telephones, an air-conditioned dog kennel and a 155-foot drawing room that out-stretches anything in California's Hearst Castle by a good 70 feet. There's no place like home, and that's what Gordon Hall, 31, is about to call it.

Hall, his wife and two (soon to be three) children will be the first people to live in the suburban Paradise Valley mansion since multimillionaire Walker McCune built it 20 years ago.

At 55,000 square feet and 152 rooms, it is no crackerbox -- but Hall plans to increase its floor space to 150,000 square feet and 380 rooms. McCune, who inherited his wealth and died a recluse, wanted no part of his $6 million palace when he and his wife separated on the eve of its completion. And why does Hall, a real estate developer who made his fortune in the health-spa business, want to live there?

"Ego, self-gratification, and it's a wonderful place for a family to grow up," Hall said. " . . . I enjoy living extravagantly, and I work hard so I can live that way."

Hall bought the three-level mansion on 6.1 acres for slightly less than $5 million. Its replacement value is set at $30 million for insurance purposes. He estimates his property taxes at $40,000 a year and says he makes the mansion available to various charities for money-making tours that produce more than $1 million a year in contributions.

"I'm part of America," he said. Surely it was just a coincidence that he closed the deal for the mansion on July 4, 1983.

While a crew of workmen ranging up to as many as 200 a day puts the final touches on the house, the Halls are living in the caretakers' quarters -- a comfortable 3,500 square feet.

As he leads a visitor on a tour of the mansion, Hall barks orders to workmen and describes points of interest, among them the solid brass hinges installed on all the doors during remodeling, at a cost of $20,000.

Other touches include an indoor ice-skating rink; an underground racquetball court; a 9,000 square foot master suite that Hall calls "a home within a home," which includes a 3,000-square-foot master bedroom; a 14-foot deep Olympic-sized swimming pool; a 15-jet waterfall that pumps 1,300 gallons a minute from a gazebo into the pool; a movie theater with a 15-by-25-foot screen; 77 heating and air-conditioning zones, and a 14-car garage. (The Halls populate it with six vehicles ranging from a Ferrari to a van.)

For the children, ages 2 1/2 and 1, there is a $30,000 swing set that would put most playgrounds to shame and will easily accommodate their third child, due next month.

The master suite has a security panel of 29 TV monitors that, among other things, will enable Hall to keep an eye on the children's bedrooms. There are about 50 cameras inside and out, and a security force of 18 to keep intruders away. Guards at the main, steel-grated gate are protected by bullet-proof glass.

Between McCune's stewardship and Hall's, various owners have used the mansion as a resort and a setting for weddings and receptions. A church once expressed an interest in purchasing the property -- and at one time, an owner was willing to throw in a Rolls Royce to anyone who would take the mansion off his hands.

But it has never been lived in as McCune intended it to be. Until Hall took over, the mansion was furnished with virtually new appliances dating back to the '60s.

When the work crews finish this fall, Hall says he hopes to give the nation a house tour on a segment of the television series "Lifestyles of the Rich and Famous" -- not bad for a man whose formal education stopped after high school. Book-learning, he said, provides for survival, not success.

Hall spent his first 19 years in San Diego, dabbled briefly in commercial fishing and served three years, three months and three days (by his own meticulous count) in the Army. Thereafter he went to work at a 24-Hour Nautilus Health Spa as a fitness instructor, moving quickly into sales, management and, eventually, ownership. At his peak in the business, he owned 17 outlets in California, Arizona and Texas.

A few years ago, Hall sold his health club interests and has diversified into commercial real estate development, jewelry stores, banking, construction and air conditioning. He wants to build a 72-story skyscraper near downtown Phoenix. It would be the tallest structure in the city.

Still a fitness enthusiast, Hall swims and plays racquetball. He says he reads up to three books a week, especially biographies of the super-rich.

"Money breeds freedom," he said. "When you have enough, you can decide when to work, how much time you're going to spend working, and how much time you're going to spend with your family. My priority is with my family."

Hall's ego is etched throughout the mansion. The letter "H" appears subtly in the design on the bottom of the pool, in certain light fixtures and various nooks and crannies. They're not noticeable enough to affect selling the place, he says.

"You've got to plan," Hall said. "Failing to plan is planning to fail."