In a letter, Adorno refers to "Negative Dialectics" shortly after its publication among his writings as "the philosophical main work, if I may say so." This significant importance that the work held for Adorno is reflected not only in the long time he spent writing the book but also in the extensive history that its central motifs have in his thinking. Adorno understands philosophical clarification of concepts, the work on "concept and categories" of a negative dialectic, as a dialectical transition to substantive thinking - and he pursues this here as well. This has implications for the form of the cooperative commentary attempted in this volume. Commenting on Adorno's "Negative Dialectics" can only succeed with the awareness of the insurmountable gap that separates the commentary from this text.