Aside from reading and referencing a wide range of literature, Kitaj also used books as a literal material inspiration in some of his work. Nat Lib fuses the superficial appearance of a bookshelf with the idea of a natural wilderness. (The title, inscribed on one of the stretcher bars on the reverse, is presumably an abbreviation of ‘natural library’.) The whole canvas was initially coated with a crimson red primer, over which Kitaj accumulated broad bands of contrasting colours and fragmentary collage. The red verticals, horizontals and diagonals are negative forms created by exposing areas of the ground: a rectilinear latticework divides the picture surface into five tiers, a framework redolent of a bookcase, while a series of diagonals breaks free of this structure to suggest tree trunks. Painted scraps of paper represent boulders. A loose effect of woodland arises, even as the sharply defined shapes and glaring colour scheme thwart the painting’s tentative naturalistic allusions. Within its highly formalised terms, Nat Lib sets up a playful interaction between unbounded nature and the closeted, civilised world of books. The theme of naturalism versus artistry was one of those pictorial tenets established in the Renaissance that Kitaj provocatively laid bare in his ‘collagist’ work of the sixties.

The landscape of Nat Lib is populated by a reclining figure, who rests his head on his hand in the gesture of the melancholy man. The figure variously resembles a slumbering shepherd, a dreaming biblical figure (either Jacob or Joseph) and a daemonic river god. It was perhaps transposed from an illustration in the Journal of the Warburg and Courtauld Institutes. Alongside fragments of marbled and decoratively printed papers, some of the collage in Nat Lib comes from an etching entitled Magnolia Grandiflora (1885) by the Arts and Crafts artist George Woolliscroft Rhead (1855–1920). Kitaj had two impressions of the etching, and the figure’s face appears twice at the centre left-hand side of the painting.

The size and ambition of Kitaj’s large-scale canvases were partly encouraged by a peripheral awareness of New York abstract painting, especially the work of Willem de Kooning. In 1965, the American curator Maurice Tuchman could assert that ‘[a] basic pictorial principle of R. B. Kitaj’s work was gleaned from Abstract Expressionism: to make the entire picture surface active at all points.’ Kitaj mostly used standardised measurements for his canvases, and Nat Lib measures 60 by 48 inches – the same dimensions as other works from 1962 including Welcome Every Dread Delight, Interior/Dan Chatterton’s Town House [L44] and Rats and Roses [L47].