Of course no art, abstract or otherwise, is devoid of content (which doesn’t mean that there isn’t plenty of hollow work around). All art has meaning, intended or not, and part of the meaning of Mr. Richter’s is precisely to keep meaning on the move, to hide it, change it, multiply it, undermine it, all the while couching these feints and thrusts in visually ingratiating forms.  Which brings us to the 50 drawings in the show, done in graphite, ink and watercolor on paper, dating from 1966 to 2005. A traditionally trained painter (an East German Socialist Realist in his youth) under the sway of Pop Art and Conceptualism, Mr. Richter, early in his career, viewed drawing — and its history as a vehicle for virtuosity — with suspicion, if not disdain. The only way he could approach it was indirectly, by taking its conventions apart, exposing its artifice.  This is what he did in the large 1968 graphite drawing called “Mountains.” To create it, he first took a snapshot of a mountain landscape, that staple of German Romanticism. He then turned the photograph into a slide, projected the slide onto paper and drew the projected image. The result looks sort of like a mountain range but, clunkily traced, it resembles other things too: a hulking creature with staring eyes, a loaf of rye bread, a blob of inanimate matter, a space station.  If “Mountains” turned out to be an elaborate joke about drawing’s vaunted capacity for realistic depiction, in another piece two years earlier Mr. Richter addressed its treasured reputation as an intimately personal medium. Again, he used mechanical intervention to make his point. He attached his pencil to an electric handle drill, plugged in the drill and went to work on a sheet of paper. The resulting clusters of jittery lines look more like termite tracks than a signature style.  In other drawings from the ’60s, Mr. Richter played around with architectural forms. One prophetic sketch shows the layout of a gallery installation of large, faintly lined drawings or paintings. Structural images continued into the ’70s, gradually growing more abstract — space opened up, line disengaged itself from representation — until, in the ’80s, abstraction more or less took over, though with no fixed themes or styles.  Certain drawings seem to imitate, in graphite, the look and texture of paint strokes not so different from the big, artificially processed ones in Mr. Richter’s oil paintings of the time. And there are watercolor drawings that are really miniatures of those paintings, done in aquatic green and blue and rich vermilion.  These pieces look freely gestural, but they aren’t: they’re products of chance. Mr. Richter made them pouring paint onto the paper, then distributing it by tilting the sheet this way and that.  I don’t know how he executed several graphite works from 1986 that consist of little more than tangles of looping scribbles. These are barely drawings at all in the conventional sense of being deliberate designs. Yet from the same year we find what looks like a rough, adamant sketch of a skull, and from the year before an exquisitely modulated image of a nude female torso, a tour de force of academic realism that seems to have arrived from a different world.  Anyone familiar with Mr. Richter’s painting knows that he uses similarly contrasting images and styles in that medium, as if telling us that he planned to keep his options open. This has allowed him to sample from a range of art histories without swearing allegiance to any, to make a sweeping formal investigation of painting without declaring his absolute faith in it.  In 1999, Mr. Richter agreed to a proposal by the Kunstmuseum Winterthur in Zurich to do an exhibition of his drawings, accompanied by a catalogue raisonné. For the occasion he made 45 new pieces. Several are at the Drawing Center, and they are extraordinary. In them, one senses that a long-maintained distance from the medium is gone; the artist is engaging drawing on its own material terms.  The 1999 pieces, over all, are elaborately tactile looking. Entire sheets are covered with a layer of lightly rubbed graphite that brings out the grain of the paper and gives it graphic life. Areas of smudging create an illusion of shadowy spatial depth, against and within which linear forms float. In addition, there is lots of patterning: clouds of black dots trailing cometlike tails form drifting nebulae, which recur from piece to piece, helping to give the group cohesion.  Several of these components are both simplified and amplified in a set of four exceptionally large drawings from 2005, the most recent works in the show. Vertically oriented, they are entirely abstract but with passages of volumetric shading that suggest a concealed third dimension. Like Mr. Richter’s “Four Panes of Glass” from 1967 — and the panels in the ’60s gallery drawing — they’re environmental in scale, the size of the doors or tall windows big enough to walk into. Yet they don’t invite entry. Something about them is closed off. As with most of this artist’s work, access, apparently encouraged, goes just so far.  These drawings, which are really a single piece, hang together on one wall. But otherwise the show, organized by Gavin Delahunty, a curator at the Middlesbrough Institute of Modern Art in England, mixes work from different eras, often in clusters of pieces set on shelves. This is a smart arrangement; it points up consistencies over a career’s span but also creates an impression of surprise and variety in the work as a whole.  This is particularly important in a show that invites careful, lingering scrutiny from start to finish. In the end Mr. Richter remains as enigmatic an artist as ever. Whatever questions you ask of his art still yield conflicting answers. But you won’t find a more intimate setting for asking those questions than this one.  “Gerhard Richter: ‘Lines Which Do Not Exist’ ” opens Saturday and continues through Nov. 18 at the Drawing Center, 35 Wooster Street, SoHo; drawingcenter.org.  A version of this review appears in print on September 10, 2010, on Page C21 of the New York edition with the headline: Building An Art Of Virtuoso Ambiguity. Order Reprints| Today's Paper|Subscribe
The survey of mostly abstract Gerhard Richter drawings at the Drawing Center is a reminder of the ways Mr. Richter is an artist for many genres, styles and seasons.