All the works studied in this volume have been published before, with the exception of a few new fragmentary texts in the revised appendices 5.3 and 5.4. The present detailed investigation takes it as excuse that while these works are often caled as witnesses in support of various philological arguments, no unified attempt to evaluate them in their context as the products of an ancient scholarly discipline has so far appeared. The Author tries to show that current analyses of the Sumerian forms into tenses or 'aspects' are based on a misunderstanding of the way the Babylonians set some of their tenses (or aspects or whatever they are) against Sumerian forms in these grammatical texts. Then the Author describes the various ways in which the choice of forms may operate in Sumerian, and finally makes a suggestion as to how these might have developed.