Peter J. Gentry provides a complete and full introduction to the critical edition of Ecclesiastes in the Göttingen Septuaginta series along with user-friendly explanations for non-specialists as well as detailed documentation to demonstrate the basis for the critical text of Greek Ecclesiastes.
Text History volumes supporting the critical editions in the Göttingen Septuaginta usually provide evidence and lists to document and demonstrate the recensions existing in the textual history and the best methodology for arriving at the earliest form of the text that we can reach.
Gentry's Text History volume provides, in addition, a complete and full introduction which was not given in the critical edition. Since this introduction is in English, it will aid English-speaking scholars who find access to the critical editions difficult because the introductions are in German.