You were supposed to make my life easier!
Thank you all for the reccies. That's just why this forum never fails to amaze me.
I find myself leaning toward the Blair books and the U-boat Commander's Handbook, at least for this round.
Though I do go to Flensburg about once a year, and should read up on Luth before the next time.
So many books, so little time!
I second Flag4's suggestion to make a sticky thread about U-boat books.