Sneak peek at MONA's $100m underground library

With a price tag of more than $100 million, an R-rated section and original handwritten David Bowie lyrics, MONA's half-underground extension contains far from your regular library.

The new library of Hobart's often-controversial museum and gallery opens on Sunday after four years of construction and the excavation of eight Olympic swimming pools' worth of rubble.

It is the brainchild of MONA owner David Walsh, who grew up in the city's surrounding northern suburbs with a library card as his "best friend".

Named Phrontisterion - the Greek word for place of thinking - it contains 30,000 books from Walsh's personal collection, including some from his childhood.

It operates like a reference library, where visitors can peruse and read but nothing can be borrowed.

The traditional method for cataloguing books has been thrown out the door - they're collated only by theme.

Among the two levels are sections including history, fantasy, science fiction, actual science, music, sex and death.

There's a first folio from the 1620s of William Shakespeare's work. It sits behind glass, but a carefully crafted digital double allows readers to flip the pages virtually.

A children's area features Australian classics and there is a corner dedicated to one of Walsh's favourites, musician Bowie.

"If you really want to know David Walsh, browse his bookshelves," MONA's librarian Mary Lijnzaad says.

Walsh made his fortune by developing a system to bet on horse racing and sport and opened MONA in 2011, sparking a wave of Tasmanian tourism.

The new wing, which also contains a 40-metre sandstone tunnel and a room behind a hidden bookshelf door, is the biggest addition to MONA since it opened.

Ms Lijnzaad said the library was about fostering curiosity.

"We've somehow lost the enjoyment of reading. Maybe that's a technology thing. We're used to short, sharp sound bites," she said.

"We don't want people to come in and feel they have to be educated or that it's a formal thing.

"We want people to come in and enjoy the space, pick up a book, enjoy it, or ignore it."

In a post online, Walsh described his first library card as a great leveller.

"(It was) the thing that gave impoverished child-me a chance to seek," he said.

"I wasn't so impoverished at all, because I lived in a society that, despite its many failures, put libraries in suburbs, books in hands, and opportunity within reach."