"A lot of people think they make better art when they're drunk, but they don't," said the born-again bad boy. "Everything is better when you are sober." Now that Hirst's zipped up his flashy lifestyle and his fly (once dubbed "Dick Flasher" for regularly "whipping it out" in SoHo dives at the slightest provocation), what's he getting up to?

Hirst has recently covered a 220-seat catamaran that cruises the Thames "Tate to Tate," from Tate Modern on one side of the river to Tate Britain on the other, with his trademark multi-colored spots. The 20-minute trip, beginning from a new pier in front of the Tate Modern, designed by London Eye architects Marks and Barfield, costs £4.50 -- a bargain considering the first few thousand tickets were limited-edition artworks challenging the "accepted conventions concerning bus tickets." Hirst is no stranger to river life -- when in London from his country estate, the artist and his family live on a luxurious narrow boat moored on the Thames.

Hirst has also begun to tackle Christian themes that will undoubtedly spark controversy. One project in the pipeline is a version of Leonardo's Last Supper in which Christ and the apostles are represented by 13 ping-pong balls floating atop 13 fountains of red wine spurting out of medical tubing.

A more gruesome piece features three crucified cows, stomachs splayed, impaled on crosses of steel. Shades of the Austrian Aktionist Herman Nitsch.

Perhaps most ambitious is Hirst's 22-foot-tall, polychromed bronze sculpture of a 1950s-vintage lame beggar christened Charity. In production at the Pangolin Editions foundry near Stroud, Charity is another "ready-made" production like Hymn, which was based on a mass-produced plastic toy of a man's ecorché body and was supposedly bought for £1 million by the Saatchi Gallery. The new sculpture is derived from the post-war charity-collection boxes that once stood outside English shops, done in the form of a little girl with a callipered leg holding a teddy bear in one arm and a "Help Spastics" collection tin in the other.

In Hirst's version the collection box is busted open and the coins are strewn all over the floor. Charity is slated to go up in Hoxton Square Park, just in front of Jay Jopling's White Cube gallery, where Hirst shows. The bronze behemoth will be on display in September, coinciding with Hirst's forthcoming solo show -- if Joplin can obtain planning permission from local residents, that is.

To make the deadline, Joplin's spinners have been working overtime. According to the White Cube planning application, "Charity is a public monument for the 21st century, speaking of injustice, erosion of values and robbing charity." Council members were unimpressed. "He better start saying his prayers, because he hasn't a chance in hell," said one, uncannily.

Organized by the artist herself, the retrospective represents most of the major turning points of her career, and a clear trajectory emerges -- the show begins with a big bang and ends with a fizz. The early works made between 1961 and 1968 are undoubtedly her finest efforts, and still deliver a shocking jolt of optical energy 40 years after their making. With eye-trembler titles that speak for themselves, such pieces as Arrest, Disturbance, Tremor, Current, Shiver, Burn and Blaze exude a psychological exhilaration that later works simply lack.

Riley's undulating, black-and-white bands became the syntax of Op Art, as well as a major motif of the hallucinatory 1960s, bowdlerized into psychedelic wallpaper and printed plastic of Swinging London mini-dresses.

Riley's serious art-world success was pillaged wholesale by the design and fashion industries. Richard Shops was one of many that traduced her Op Art as textile designs, with a line called "Clever Clothes." Not so clever, according to Riley, who said, "That upset me very much. My paintings were made to work against a flat surface and very particularly at a certain scale. This is completely destroyed when wrapped round a human figure, rendered completely pointless."

Seconds after encountering masterpieces like Shiver, the viewer is visually besieged. The eyes begin to flutter, causing a sense of odd pulses and the inability to pull focus. The painting starts to vibrate uncontrollably. A drugless hallucination of impossible colors and patterns emerge. Although fixed, the painting appears to literally shiver, the kinetic effect increasing the harder you stare. The painting becomes a phenomenon, packed with mind-bending effects causing physical "sensations," rather than remaining a mere "representation" in the usual sense.

Riley's path to optical aggression began in her youth. During WW II, while her father was off fighting, her mother moved the eight-year-old Riley to rural Cornwall, in southwest England. In her essay, The Pleasures of Sight, Riley describes natural phenomena that would unconsciously surface in her paintings years later. "Looking directly into the sun over a foreshore of rocks exposed by the tide all reduced to a violent black-and-white contrast, interspersed, here and there by the glitter of water."

Riley enrolled in art school at Goldsmiths College, where she met drawing teacher Sam Rabin. His conceptual approach to abstract representation, which sought to recreate on a two-dimensional surface visual experiences that had taken place in three dimensions, was extremely influential to his young student. "I gained an awareness that we ourselves are symmetrical structures," says Riley of her years spent doing life drawing, "and the moment that we start to move, we are changing weights, changing balances and axis."

Sadly, none of her pre-abstract, pre-Op work, nor her studies of Seurat's Pointillist paintings like Le Pont de Courbevoie (so critical to Riley's early development) is included in the show. This is a pity because the transition that occurred from 1960 to 1961 is the most startling leap of Riley's career.

Also missing is Pink Landscape of 1960, Riley's attempt to capture the intense heat on an Italian plain in midsummer. Frustrated that the painting didn't vibrate or glitter like her source, Riley decided that instead of starting from an experience of nature and trying to recreate it on canvas, she would invert the process and find out what could be done on canvas first.

The Tate retrospective includes only 56 of her paintings, perhaps in part because she has worked so much in series, which use the same colors and graphic formats. After her productions of the '60s, the show proceeds through one experiment with optical delusion after another, and each seems to merge into the next. While the works from the '60s and early '70s use dramatic contrasts and events, those of the '90s (like Rêve, Evoë and Lagoon) pursue a unity and fluidity, dispensing with any sort of charged optical effect. One step away from landscapes, the late paintings regress to a more typical form of abstraction, a Matisse-like lyricism that is almost a return to representation.