Can you please suggest some books on Software Architecture, which should talk about how to design software at module level and how those modules will interact. There are numerous books which talks about design patterns which are mostly low level details. I know low level details are also important, but I want list of good design architecture book.
Please also suggest some books which talks about case studies of software architecture.
I think this is the book that came to mind when I first read this question. It talks about various architectural styles like pipes-and-filters, blackboard systems, etc. It's an oldie, and I'll let you judge whether it's a 'goodie'.
Pattern Oriented Software Architecture
I also particularly like these two, especially the first. The second starts to dig into lower level design patterns, but it's still awesome in various spots:
Enterprise Integration Patterns
Patterns of Enterprise Application Architecture
I hope these are what you had in mind.