The poetic debut of A.Mackus is "Elegies" (1950). In this book the poet resembles many minor nostalgic poets of Lithuanian emigration, who lamented their abandoned motherland and glorified the hope to come back. The nostalgia of motherland, particles of images of Vilnius, cherished memories of childhood, dreams and everyday realities - these are frequent themes of verses of this book.
The second book, "His Is the Earth" (1959), was favourably accepted by critics. To all questions the poet finds only negative answers: there is no place for joy on the earth, the life is a meaningless emptiness, where the only reality and the only meaningful thing is death. Only death will liberate from pain and solitude, the conditions of poet's life.
For the book "Generation and Foster Children of Unadorned Language" (1962) the author was honoured with literary award. The tragic note rings throughout the cycle. A.Mackus rejects traditional in poetry means of performance and sonority of the verse, and approaches the conceptual speech and rough prosaic talk.
The last book of poetry by A.Mackus, "Chapel B" (1965), is dedicated to writer A.Škėma, who perished tragically. It was published after the death of the poet and sounds like a necrology to himself. This collection is a complicated funeral song, where erupts both the grief of the poet himself for a dead friend, and for a cruel fate of Lithuanians in exile in general. Thus, in his last works A.Mackus remains a preacher of a hopeless night and of eternal death of a man, and in this way he is an unique representative of materialistic existentialism in Lithuanian literature.