LUNCHEON AT THE CAFE RIDICULOUS <i> by Alice Kahn (Poseidon Press: $17.95; 285 pp.) </i>

There are few topics that Alice Kahn has not considered, slouched at her home computer, no doubt in direct defiance of her mother’s lifelong admonishments to sit up straight. In fact, Kahn’s combined motherliness and rebellion at becoming the older generation gives her the familiar voice that speaks to so many in her syndicated newspaper columns: the child of the 1960s who is falling back on a few of the habits of the parents whose habits she is so in the habit of deploring.

Kahn’s specialty is skewering fads, for which she always has a cute term--”layette envy,” for example. Another forte is offering tongue-in-cheek advice for those dilemmas unique to contemporary life: Wouldn’t choosing a therapist be much easier if we could run personal ads for them? “Woman who loves too much seeks handsome, married hypnotherapist. No head trips, please,” she offers.