The last several decades have seen significant developments to the revolving-flats card and much research has been published on the fundamentals of the carding process. There are still, however, contradictions in the detailed explanation of fibre behaviour during carding and in the effectiveness of certain developments widely accepted as beneficial. This paper presents a critical review of the literature concerning the way fibre mass is disentangled into individual fibres to form a card sliver and the effectiveness of principal machine components. Areas are indicated where further research is necessary to resolve contradictory views and further the understanding of the process.