Some of the books in this annotated bibliography on enterprise integration are dated now, but most of them are still relevant because they're not limited to a specific technology. I own almost all of the books listed here and have read all of the good ones :-) Also see books I authored or co-authored.

	Software Architecture: Perspectives on an Emerging Discipline Mary Shaw, Garlan David Prentice Hall, 1996
	The definitive text on software architecture and architectural styles.
	Software Architecture in Practice, 2nd Edition Len Bass, Paul Clements, Rick Kazman Addison-Wesley, 2003
	Part of a whole series on architecture from the SEI. Generally, these books are very throrough, but for my taste too many examples and case studies are pulled from military projects or embedded systems. These types of systems typically lend themselves to a very rigorous top-down architecture and design approach, unlike today's business applications that are all about changing requirements.