Books and computer access are still the ultimate lures, but the soon-to-open Mattapan branch library rewards visitors with a public space that would be well-suited to a prestigious college campus. The Blue Hill Avenue building, which will open to the public during an official celebration on Saturday morning, got a final thumbs-up from Mayor Tom Menino, who toured it on Monday morning along with the architect, library staff and other elected officials.

"Very impressive," was Menino's assessment of the new building, which was built for $16.7 million at the high-profile corner of Babson Street and Blue Hill. "You have a sense of community with the openness and the direct lighting you have. The young adults room has privacy and access to computers. The childrens' room is spectacular. The architect did a great job in designing it."

That architect - Boston-based William L. Rawn III - is best known for his work on college campuses and is also busy creating a new central library for Cambridge. Rawn says that the Mattapan branch stands out for its use of natural wood coverings on the walls, floors and ceilings which give it a "light and airy" atmosphere. The 21,000 square foot space benefits from an open-floor plan that allows staff and patrons to see from one end of the building to the other. Separate rooms for children and young adults are encased in glass and look out upon an outdoor courtyard.

"We really wanted the front desk to be command center and have views of the whole library plus views of both the front and rear entrances," says Rawn. "There's a sense of someone always here that's aware of what's going on in the building."

In addition to a community task force appointed to oversee the project, Rawn and his firm met with focus groups of Mattapan kids who helped to inform the design of the young adults section.

"They wanted something very colorful, they wanted a lot of computers and the sense that you could make noise," Rawn said. "They knew they are louder than the rest of the library, so that room is totally soundproof. The teen librarian will be there in the afternoon from 3 o'clock on and it's a very lively place. We set up some private study rooms for those who want quieter spaces for studying."

Rita Dottin-Dixon, a Mattapan resident who served on a committee that gave input into the building's design, said the new building would change the way local residents use the library. The now-empty Hazleton Street branch, Dixon says, was not a popular stop for many in the neighborhood.

"It was dark and a lot of people were scared to go there. It just wasn't state of the art. As we go into the future, this library is much more livable," Dixon said.

She hopes that the young people who helped to pick out the materials for the interior designs will be encouraged to patronize and program the library.

Councillor Charles Yancey, who joined Monday's walk-through, echoed Menino's praise for the design. Yancey - who first pushed for a loan order to build a new library branch back in 1995 - said he thought the branch would likely become a destination for the rest of the city.

"I feel blessed to have lived long enough to see this," he said.

Menino, whose name adorns the Hyde Park branch library built a decade ago, declined an opportunity to rank Mattapan's new addition as the city's finest.

"Ahh, I can't comment because one was named after me," Menino said. "They're all different, though, because each neighborhood is different. But I haven't seen this in a library in a long time. The young adults room is very special I think.

"It tells you a lot about the people who worked on this. The community has a lot to say on what goes on here. The architect took the time to do focus groups and find out what the community wanted. They have some ownership to it."

Saturday's grand opening event at the library will include a speaking program and ribbon cutting which begins at 11 a.m. It will continue with performances and storytelling throughout the afternoon.