BORIS Johnson formally opened the South Ruislip Library and Adult Education Centre on Tuesday.
The Mayor of London was joined by his Hillingdon counterpart, Cllr Michael Markham.
The open play library has more than 2,000 books, seven PCs and four Apple Mac computers.
There is also a Starbucks coffee shop, a florist and free wi-fi.
Council leader Ray Puddifoot said: “This is the latest of our new libraries and is a fantastic facility for South Ruislip residents.
“We believe we are the only local authority in the country either rebuilding or refurbishing every one of our libraries.”
The library is open from 9.30am-9pm Monday-Thursday, 9.30am-5.30 Fridays and 9.30am-4pm on Saturdays.