In Once in a Lifetime the artist lays out a journey through the different genres of his work, from monumental group portraits to the distinctive landscapes, by way of figurative representations in a variety of formats. There are also small studies, created with a lighter and more fluid technique than that used in the final canvases, and these sketches from life take us into his laborious creative process.
The formal motifs that recur in his compositions - female characters, male figures, alone or in company, against neutral backgrounds or in everyday settings, as well as elements of nature - are treated with a poetic intensity that is sometimes full of life and at other times somewhat more melancholy.
Alex Katz has been considered by some critics as a precursor of Pop Art for his personal interpretation of objective figuration in the early sixties. He shares with the artists of this movement the influence of mass media (the iconic transformation of its images, repetition and fragmentation of motifs, modes of representation drawn from cinema and advertising); the use of flat, bright colors; and also a preference for scenes of daily life, seemingly inconsequential, ephemeral moments that he raises to the level of art with freshness and elegance. But his interest in exploring how light modulates the surface of the painting, in contrast to the graphic style of Pop Art, differentiates him from this movement.