The 81st Avenue Library cost more than $14 million to build at a time when many libraries are cutting hours.
Mayor Jean Quan was on hand for Wednesday's dedication and said she has been talking to young gang members about keeping a one block radius safe for visitors.
Councilman Larry Reid calls it the jewel of his district.
The library will house 30,000 books, DVDs and CDs, along with 62 computers.
It officially opens this Saturday.