Salesforce Tower is the tallest high-rise in San Francisco, and a complex bundle of contradictions.

The 1,070-foot shaft, with its tapered form of metal and glass, is a well-tailored behemoth. Immense but understated. Overwhelming yet refined. A study in thick-walled minimalism that seems to hover more than soar.

All of which makes for a nuanced tower, conscientious and self-assured even as it reorients the skyline and redefines San Francisco’s visual image. But there’s also an air of detachment, as if the creators were so busy being tasteful they forgot that big buildings can be fun.

In the works for a decade, and with plenty of work left to do, the 1.42 million-square-foot tower at First and Mission streets opened quietly Monday.

Salesforce workers entered clutching umbrellas emblazoned with the building logo, heading to space on floors seven through 10. The sidewalk along Mission Street is complete. The one on First Street isn’t.

As a public presence, of course, the tower has loomed large since its concrete core climbed past the 853-foot Transamerica Pyramid, our skyline-topper since 1972. Whether you’re in the Richmond District or the city of Richmond, on Mount Tamalpais or in San Mateo, the rounded summit with its perforated metal cap seems to have been photo-shopped into long-open vistas.

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That prominence is enough to alienate many longtime Bay Area residents, no matter the actual design. The curved shaft also has undeniable phallic connotations, though it’s a nod to classical obelisks.

But give the architects credit — they understand that size isn’t the only thing that matters. Visual grace notes are as important as the imposing first impression.

The design is by Pelli Clarke Pelli Architects, which also did 2002’s exquisite 560 Mission St. high-rise a block to the west. Cesar Pelli, the founder, is known for work that trends in a contemporary but conservative direction, while emphasizing a rigorous attention to fine-grain details.

This is especially true with towers as dominant as San Francisco’s new peak, which was developed by Boston Properties and Hines: The goal was something “very tall, very big, but still polite and appropriate,” Pelli, now 91, said last year at the firm’s studio in Connecticut.

The word “appropriate” is subjective. The thoroughness and care of the near-finished product is undeniable.

The bottom third of the tower rises straight from the street. Then it slopes in gently, floor by floor. The ascension is methodical as well, with each side of the tower the same and each corner marked by a broad soft curve.

The top occupiable space is the 61st floor, which Salesforce will offer to community nonprofits for use after it is completed this fall. The ceiling is 920 feet in the air; the tower’s final 150 feet are largely ornamental, with an enclosed mechanical space and then a perforated metal crown that will be illuminated at night by local artist Jim Campbell’s LED installation.

While the office floors are skinned in glass, an outer lattice of white aluminum fins and sunshades extend out as much as 2 feet beyond the silvery glass skin. On the lower floors, looking up from nearby, the lines are distinct. Above that the lattice becomes a massive but elegant grid that narrows and tightens and then shifts to sky.

The one break in the symmetry is on Mission Street, where the tall lobby with its white marble walls and gold-hued limestone floor is contained within a convex wall of ultra-clear glass. It’s pulled in several feet from the tower’s outer edge, which allows the sidewalk to widen and opens up views to the plaza-to-be.

That gesture is enhanced by the way the lobby’s glass walls are held in place — not with vertical frames, but two horizontal steel bands set well above the revolving doors. Not only that, the bands are punched with holes that mimic the shape of the tower when seen from above.

“This allows extra daylight to pass through,” said Ed Dionne, the firm’s principal in charge of the project who has worked on the tower since the 2007 competition for the prominent site. “It’s a little bit more delicate.”

There’s delicacy of a different sort above: The sun shades above each window are angled and have slight perforations, a twist that adds unexpected depth.

Small touches like this capture the effort by the architects to, in a sense, bring Salesforce Tower down to size.

As large as the form might be, the soft curves allow your eyes to glide past if so desired. Above, the clean white metal grid allows the new structure to play off the natural environment. Light becomes an element of the design, a texture that shifts tone depending on the color of the sky and the angle of the sun.

If there’s a downside to such efforts to fit it, it’s that in the process, Pelli Clarke Pelli sacrificed the exuberance that make the best tall towers memorable. Think of the Chrysler Building in New York or Chicago’s John Hancock tower: One has the giddy feel of the jazz age while the other embodies the muscular brawn of the industrial Midwest. Both, though, are symbols of their cities.

In San Francisco there is Timothy Pflueger’s 140 New Montgomery St., the old Pacific Telephone Building, a chiseled cliff complete with terra-cotta eagles up high. Transamerica Pyramid isn’t nearly so compelling inch-for-inch, but its steep relentless ascent is unforgettable.

Salesforce Tower, at least for now, falls short of those other peaks. It is what it is — a signature building done by a firm that works on four continents, hired by a developer of similarly wide reach.

Architecture buffs already dismiss Salesforce Tower as old hat, another Pelli Clarke Pelli shaft with a tapered silhouette — just like the International Finance Centre in Hong Kong or Torre Costanera in Santiago, Chile.

This is overly simplistic — in Hong Kong, for instance, the 1,352-foot shaft has a series of small notched setbacks as it climbs. Salesforce Tower is one smooth ascent. From a distance, you read it floor by floor, rather than with the energetic charge of having your eyes pulled upward toward the heavens.

As I said early on, Salesforce Tower is still a work in progress.

The half-acre plaza at Mission and Fremont streets won’t be ready until late spring. The same goes for Campbell’s 11,000-LED vision for the crown. There’s also restaurant space waiting to be filled along First Street.

The most truly public feature will be the fifth-floor bridge leading to the 5.4-acre park atop the new Transbay Transit Center. Until the latter opens in late spring or early summer, the former will be off-limits as well.

When all these elements are complete, the newcomer will begin to feel at home. And while it won’t ever gain visual swagger, you might come to like it more than you expect.