The study A Simple Song - The Art of Composition. Miloslav Kabelac's Six Lullabies (1956) focuses in particular on the solo vocal part of this composition which is based on folk poetry and scored for alto solo, small female choir and instrumental ensemble. The author begins by explaining the two principal reasons behind the composer's choice of text - its meaning and its structure. The study offers detailed analysis of the musical form, the use of rhythmic structure and the melodic attributes of the vocal line. Step by step, the author reveals the cyclic plan of the six songs; the extension of the multi-directional composition into a unique space: the six autonomous lyric moments, the interior continuous undulating, the arch-like span, and the open-ended cycle line of flight. The writer's interest in French phenomenology is present here.