Janet is 40 years old, but she has said that she feels half her age, and her breakthrough as a pop phenomenon occurred in 1986 -- hence the title of her ninth album.

20 Y.O.

is her safest and tamest work since 1984's Dream Street, not only because she couldn't have possibly taken her sexed-up confessional routine beyond the tidbits and techniques divulged throughout 2004's Damita Jo.

With only a few exceptions, 20 Y.O.

provides further refinements of the fun, flirtatious, midtempo songs of her past several albums.

This is not a problem.

Even when there are clear instances where Janet, along with principal collaborators Jermaine Dupri, Johnta Austin, Jimmy Jam, and Terry Lewis, are taking an extended ride on the electro-nostalgia bandwagon -- "So Excited" samples Herbie Hancock's "Rockit," patches of "Get It Out Me" resemble Afrika Bambaataa's "Looking for the Perfect Beat," "Show Me" might not have happened without the existence of Ciara's "Goodies" -- they are too fresh and infectious to be considered knock-offs.

There are crafty analogues and references to various points in Jackson's past: "This Body"'s rock edge recalls "Black Cat" (though it's more of a strutter than a headbanger), "Daybreak" sparkles and glides like "Runaway" and "Escapade," and "Take Care" is a classic Janet ballad in the vein of "Come Back to Me." The parallels are natural enough that they don't seem all that premeditated.

Almost as significantly, the album is roughly 20 minutes shorter than usual, with only a handful of interludes, so there's little meandering, in turn making it easier to become familiar with the curves.

What really differentiates the album from its predecessors is that there's almost no trace of tension to be heard.

It's all about fooling around and being in love.

Janet's gang of assistants is on top of its game, and Janet herself has remembered that she doesn't have to be willfully explicit or eclectic to make a sexy and wholly enjoyable album.