Luther on Women: A Sourcebook. The book provides an anthology of Luther's main writings about women. Someone with Luther's Works has this material already, but having some of the most relevant documents in one collection is helpful.
The book provides a brief introduction outlining the contemporary debate on Luther's view. The entire introduction is available here. Briefly, these are the two basic positions:
1. Luther rescued marriage and women from the medieval Roman Catholic church, improving the social status of women.
2. Rescuing marriage from the medieval Roman Catholic church is not equivalent to rescuing women. The social status of women was not improved, rather, women were relegated to the household.
In the introduction, the authors also make some other interesting conclusions about Luther's view:
1. Women "were less rational than males in a scheme within which rational equated with better" (p.10),
2. Women "were more inclined toward emotion" (p. 10).
3. Women "could be more easily led astray than men" (p. 10).
4. "Little girls did not require and could hardly master higher learning" (p.10).
The unfortunate aspect of the introduction is that the assertions are not footnoted (and I'm too lazy at the moment to go searching for them). Certainly I would not expect a contemporary view of women from a 16th century man. It certainly is the case that women have been subjugated or treated as inferior by men throughout history, even important men with valuable historical and theological contributions.