By Sue Grafton

Henry Holt. 261 pp. $16.95

At one point in "The Maltese Falcon," Sam Spade says to his secretary Effie (who's done a little nifty detecting on her own and hasn't whoopsed at the sight of a corpse), "You're a damn good man, sister."

End of the chapter; she never gets to respond.

I keep picturing Effie, still stuck in that literary tableau vivant after 61 years, and still stuck for the right answer. Then again, aren't we all?

Woman as Good Man. Bottom line of the syllogism "All men are good; this woman is good; therefore, she's a man." And its corollary baggage that the cost of being "good" (in the sense of tough/smart) is the loss of femininity.

Quick: What's the answer?

There's a case to be made here that it's Kinsey Millhone -- professional detective, heroine of Sue Grafton's alphabet series, whose opening adventure came in " 'A' Is for Alibi" in 1982.

Kinsey's a peach. An adorable tough -- if that's not (and it's not) a contradiction in terms. She's resourceful, realistic, spontaneous and concerned for other people. Her chosen occupation as an independent eye seems entirely commensurate with everything she is. Nor does it violate the classic tradition. If the private eye hero has to be, of necessity, a relatively hard-boiled cynical loner, then so do single young women in the '90s -- which may account for the raging popularity of Sue Grafton's work.

" 'G' Is for Gumshoe" begins rapidly and well. It's the morning of our heroine's 33rd birthday and two things occur: She's hired to find an elderly person, and she learns that she herself has a contract on her head. A professional hit man is about to kill Kinsey, and three other people, for a grand-total salary of $1,500. (Life may be cheap, but this is definitely tacky.)

Kinsey, throwing caution to the wind, forges on. And so do the plot lines -- the first one evocative, the second one a mess.

Start with the good one -- the search for the wild and half-loony old lady. This one takes Kinsey into dangerous turf and the dungeons of old age -- the hospitals, nursing homes and board-and-care facilities where old people lie around "as motionless as plants" and where everybody's mother is condemned to death row.

The picture Grafton paints here is harrowing and poignant, and Kinsey's response to it ("Maybe I'd get lucky and be struck down by a beer truck before I was forced into such ignominy") has the subtle foreshadowing of Famous Last Words. What exactly strikes her down, about 30 pages later, is a dusty red pickup with a killer at the wheel. He rams her VW, viciously, repeatedly, runs it into a ditch and then closes in for the kill.

Kinsey fakes him out.

So far, so good, even modestly terrific. Only, suddenly Kinsey's in a different and a much more decisive kind of trouble and the reader's in it too. Because suddenly the plot, like the totaled VW, is veering out of control. The logic gets bumpy. The road jumps a cliff. The old lady gets ejected into deep, dark and, worst of all, derivative Gothic, and suddenly we're floating in a hard-boiled souffle'. Even the assassin turns a little bit absurd, like a character created from a villain-o-matic out of Spy Magazine.

Still, we've got Kinsey, who makes it worth the trip, and who plays it all out like a sunny Lew Archer, with a better sense of humor and a better sense of dread. In the course of her wanderings, she calls for a bodyguard -- a craggy, half-romantic tough guy named Dietz -- and the one thing eventually leads to something else (the kind of belated birthday present every girl deserves).

And of course the two mysteries are finally resolved.

A third, however, isn't: the tantalizing extracurricular question of whether this novel, in itself, is really new -- in the true sense of "hot off the writer's computer" -- or whether it was written circa 1983. Take the following clues:

A character born in 1936 is said to be 47 years old; a 5-year-old child was apparently alive in 1981. And if you can't do either of those math problems in your head, try this one: A woman born in 1900 is now 83.

I found this distracting. Extraneous questions raised their hands in my head like impatient third-graders who need to leave the room.

For example:

Is the novel supposed to be a flashback? (If so, is our Kinsey now 40 years old?)

If this is an old story line, why was it held? Did the editors find it too weak or improbable to make the top six? Or did they simply think Kinsey needed more time alone before she took on a bodyguard?

And finally, why didn't someone change the dates?

Undoubtedly, Kinsey can arrive at the truth of this and keep us all posted -- sharp and compassionate detective that she is.

The reviewer writes crime novels under several names and also teaches detective fiction.