Somewhere, lost in the vast army of unwashed, long-haired gee-you-sound-just-like-Joan Baez early 1960 girl folksingers, is Bonnie Raitt’s musical mentor, and Bonnie, ain’t that a shame, doesn’t even remember her name.

“In the summer of 1969,” Bonnie relates, “I walked into the Second Fret with Dick (Waterman). There was this chick folksinger on first and she was just terrible. Even I was better, I thought. So I turned to Dick and asked if she got paid for singing. Dick said she did, and I decided immediately singing was better than typing. So here I am.”

Former typist Bonnie Raitt is now Bonnie Raitt, Warner Bros. recording artist, and her story unwinds like a forkful of long spaghetti, possibly titled “Why Does the Redhead from L. A. Sing the Blues?” So why already?

Bonnie, now 21, grew up in Los Angeles (her father is musical actor John Raitt) and its music scene, went to a public high school, a left-wing intellectual summer camp, attended a progressive prep school and was into music ranging through the Beach Boys and Jan and Dean, to post-R and B soul music, topical ballads and folk blues.

“White rock music turned me on to black music, and my camp experience turned me onto folk. The soul music I dug led me to the blues, and then I met Dick in Cambridge and got to know all his acts, and learned some songs, and some guitar,” is the way she tells it. Learn guitar from Son House and Fred McDowell? Whew!

Self-deprecating to a fault, Bonnie doubts her ability. But a growing series of audiences and Warner Bros, noted for excellent taste, are new believers.

Striking and stately, her red hair trailing down her back, Bonnie strides onstage with two guitars, a regular old Martin and a fabulously funky all-metal antique National Steel.

She brushes a strand of hair off her face, slips her left ring finger into a whiskey bottle neck, and Lawd, she singin’ the blues.

Her voice is high and sweet, then low and musky, and notes slither from her guitar like a cutting blade. Whoops of encouragement from the audience and off she slips and slides into Robert Johnson’s “Rollin’ and Tumblin’.”

Just the sight and sound of a woman playin’ such down home Delta slide guitar (latent sexism) impresses the audience who then realize (right on! women’s lib) that not only is she good for a girl, but she’s really good.

(“Yeah,” she admits, “the chick playin’ the guitar thing can get you down. But like I told you, I don’t think I’m that good.”)

Next song is a little different, Bonnie informs the crowd, and switches back to the old wooden standby (guitar) for Steve Stills’ standout “Bluebird.”

She sings one of her own blues, a tragicomic ditty known as “Let Me Be Your Blender, Baby.” then James Taylor’s “Close Your Eyes,” and for the first time, you understand the words.

Carole King’s “You’ve Got A Friend” and another Bonnie blues and “Woodstock” and Tommy Johnson’s funky classic “Big Road” follow.

“One more song,” she tells the audience, and reached back into high school for Lenny Welch’s “Since I Fell For You.” You used to “make out” to this song, and so did I and so did Bonnie and, God, does she make it sound beautiful.

Enough praise. Bonnie’s manager, Dick, signed her with Warner’s and she just returned to Cambridge (her home and sometimes college town) after sessions in L.A. with fellow warnerworkers Ry Cooder and Randy Newman. They’re possible session men for her summer-scheduled album debut, along with her friend Mississippi Fred McDowell and Dan “Freebo” Freidberg fretless bassman for Philadelphia’s Edison Electric Band.

Her personal appearances are picking up and the money is beginning to trickle in, and true to form, she’s cynical about it.

“I can’t sing the blues,” she says. “Muddy Waters and Jimmy Reed and Son House and Fred, they can sing the blues, but me, never.”

“Anyway,” she continues, “the type of music I love will never be popular, and any chick in a gospel church can sing 50 times better than me.”

O.K., Bonnie we get the picture. You probably thought you were a lousy typist, too.