Got and read the Wiggins book a few months back - had it saved on my wish list for a while before it was even available. Got it as soon as Amazon had it to ship and really enjoyed it.
I just ordered these three:
Silent Hunters: German U-Boat Commanders of World War II
Theodore P. Savas
Lone Wolf: The Life and Death of U-Boat Ace Werner Henke
Timothy P. Mulligan
Grey Wolf, Grey Sea
E.B. Gasaway
All used from third party vendors via Amazon at pretty decent prices, each was less than $15 including shipping. Looking forward to receiving them!