Some may know her as the woman who split up The Beatles, others as the woman who warbles on music tracks, but since Yoko Ono has a major retrospective at the Serpentine Gallery this summer, you can take it she is a pretty well established, international artist as well. The exhibition spans her career from the early 1960s until present and is her first in the UK for over a decade. As always, she is concerned with the audience and artist as agent: cue audience participation, walking into walls, and the occasionally cringeworthy confessional notes.  

Yoko Ono has always been an optimist. Back in the day - before my day - she believed that "War is Over - if you want it". On entering the gallery, the very same poster slogan is the first thing ahead. The eternal hippie, Ono never fails to believe in the power of art. And good on her. Art is a powerful tool. The three piles of earth ahead are simply labelled, country 1, country 2, and 3 - the message is that war reduces us all to the same thing eventually. Her preoccupation with the anti-war movement has come to characterise her work, and was synonymous with her and John Lennon's relationship; an ever-present figure in her art and life.

In the same room are some of her works from her participation in the Fluxus group. She interacted with this group in the mid 1960s until the early 1970s, and it makes up some of her best work. The group's main proponent was George Macuinas, but included many different and notorious artists. The group's influences included the Dadaists and composer John Cage and aimed to turn the art world on its head with its do-it-yourself attitude, breaking down dependence on traditional artistic skill. This anti-commercial aesthetic in Ono's art is powerful. Nowhere else is this more evident than in her Description for Paintings or Painting to be Stepped on. Both pieces ignore the preconceived requirement of skill and attempt the blurring of art and life in a satisfying way.

Unfortunately when Ono strays from this path, her work often becomes overloaded with sentiment and there's a distinct sense of dated optimism wafting around the gallery: a needle pointing out of a plinth is titled Don’t even think about it or the tritely titled Sky TV shows a pleasant scene of a summer day's blue sky playing on a TV, in a room where the writing is literally on the wall.

With a career spanning half a century, I wonder how far she has travelled in her artistic journey. And that's my concern about this exhibition: a retrospective tends to highlight an artist’s development, their oeuvre - and Ono's doesn't seem to have evolved that much. That said, it's interesting to see some of her early performances reenacted. One room shows the video of Cut Piece, the original in 1963 and its remake in 2003. The performance (or Happening, if you want to recall the Fluxus-style name tag) shows Ono sat on a stage, slightly slumped, allowing members of the public to cut off her clothes. The original was a fantastically powerful piece, echoing sexual violence and female submission. Seeing the two played together shows the different artistic status, the reverence towards the artist and the way her audience treat her.

It's not the only thing that has been reworked either. The centrepiece to the exhibition is Amaze, a Perspex maze that invites the viewer to become the viewed, first made in 1971. If nothing else, it provides a bit of light relief from the sentiment of other pieces.

The exhibition continues outside to include the Wish Tree and an oversized all-white chessboard titled Play it by Trust. Its unwavering optimism is slightly disconcerting, particular as she shouts "Smile, I love you!" rounding up the troops for her continuing video project to collect the world's smiles. Perhaps that's part of her appeal; she's successfully positioned herself on the characterful side of bonkers, and interactive work does draw the crowds. It's worth going if only to see some of her older poignant pieces.

Yoko Ono, at Serpentine GalleryLaura Thornley reviews Yoko Ono's To The Light at the Serpentine Gallery.3