Picasso's sketchbooks. On exhibit for the first time, they show evolution of his ideas

IT isn't often we are given the opportunity to watch the inner workings of genius -- to follow the step-by-step progression of ideas that change our way of seeing or thinking, or to observe the evolution of a masterpiece from rough sketch to finished study. That, however, is exactly what we can do at the Pace Gallery here, thanks to its current exhibition of 45 of Picasso's sketchbooks.

Dating from 1900 to 1965, and chosen from the 175 produced by him, these tiny to fair-sized sketchbooks -- pictorial diaries would be a better description -- include sketches from life, detailed compositional studies, and tentative and carefully worked-out ideas for major paintings. There are also watercolor renderings, serial variations on specific themes, finished drawings, collages, and even shopping lists.

Taken all together -- and this is the first time they have been exhibited publicly -- they underscore the awesome depth, range, and fertility of Picasso's talent and imagination.

We cannot, of course, see the majority of the drawings, although the gallery staff has done its best to open each sketchbook to its most interesting page. A few of the books have been disassembled to permit several studies to be shown, and a number of sketches are displayed as reproductions.

Anyone the least bit interested in Picasso, drawing, the evolution of modernism, or the nature of creativity will be fascinated by this exhibition. And anyone with ambitions to be an artist will be both exhilarated and humbled by it. It isn't just his genius that's impressive; it's the way it was applied, the way it is pushed to its apparent limits in one area, permitted to be playful or to show-off in another, and then allowed, in yet another, to tackle something totally new and unheard of.

Looking at these sketches, we get the impression that this surge of creative energy never dried up, that it just kept coming, and that Picasso had to fill sketchbook after sketchbook, execute one painting or print after another, just to keep up.

We also cannot help but be impressed by the authority of so much of what bubbled up and was caught ``on the wing,'' as it were. Even some of the most doodle-like of these images have the impact of an irrefutable argument; they could easily hold their own next to similar quick studies by Rembrandt or Rubens.

No matter where we look, we see evidence of Picasso's restless and inquisitive mind. There are tiny sketches of animals and children that would enchant anyone not the least interested in modernism; a number of Cubist studies that would only be of interest to those who are; a few highly finished classical drawings that Raphael probably would have admired; some swiftly executed heads and figures in an ink-wash technique that seems almost Japanese; and any number of other works that cannot easily be categorized.

It is, in short, an exhibition that shouldn't be missed. I particularly recommend it to those who have the desire to draw, but who feel they lack the necessary skills to do it well. Looking at the sketchbooks, one quickly realizes not only that even genius makes mistakes, but that drawing is actually an educational process, a simple trial-and-error method of acquiring insight and knowledge that is available to everyone, regardless of training or skill. If it does nothing more than make this point, this show will have been of inestimable value.

Fortunately, after its closing at the Pace Gallery on Aug. 1, it will begin an international tour at the Royal Academy in London in September and will then be seen in seven additional American and seven additional Euro pean cities. Plans for the tour will be announced shortly by American Express, its sponsor. Other shows: drawings, watercolors, sculptures

Two shows, one of more than usual interest, and the other of greater than normal curiosity value, are on view at Acquavella Galleries here.``Nineteenth and 20th Century Master Drawings and Watercolors'' presents 37 fair to superb works on paper by 21 famous names of the past 150 years. The earliest is a tiny watercolor of a ``Seated Moroccan'' by Delacroix, and the most recent are two colorful, if rather minor, gouaches by Chagall. In between, there are excellent pieces by Barye, Vuillard, Redon, Forain, Mir'o, Tanguy, and Diebenkorn -- as well as a first-rate study of Misia Natanson by Lautrec.

``From the Figure'' consists of several recent bronzes and drawings of the female figure by Anthony Caro. Although famous primarily for his abstract work in steel, Caro began his career with a few chunky figurative pieces, an approach to sculpture he has obviously not altogether outgrown.

He writes: ``During the summer of 1983 . . . I had the opportunity to draw regularly from the model . . . and I enjoyed this so much that the following year I resolved to sculpt her in clay . . . The experience is rewarding . . . I set time aside directly for it; and I have no doubt it will come to feed the mainstream of my work.''

It is still too early to tell whether or not it will. It is also a bit too early, I'm afraid, for works representing his renewed interest in the figure to be on public display. A wait of a year or two would have been wise. It's not that these pieces aren't interesting and competent, only that they are still too tentative to be worthy of his name.

At Acquavella Galleries, 18 East 79th Street, through May 14. The master drawings exhibit at the same gallery will remain on view through June 10.