Occasionally you read a book that flips you on your head and gives you a unique spin on things. I've just found two books that fit the bill:
'Security Metrics' by Andrew Jaquith
'Beautiful Security' by Andy Oram, John Viega
I've almost finished Security Metrics and just started reading spot chapters from Beautiful Security. I fully intend on writing reviews here for both shortly but please don't wait for my review.
I strongly recommend you read these books. I am finding both fascinating reads and I can assure you that these will give you new insights and add real value to your work.