[c-nsp] Advice - CCNA Security certification

[Subba Rao]

Hi,

I want to start specializing in Cisco Security certifications.  Does
anyone have a good book to recommend to prepare for this certification?
 My work experience is mostly in the assessments area concentrating on
OS and networks.  I am not a network admin though however I do
understand the underlying technologies/protocols.

Any advice is appreciated.  Thank you in advance.

Subba Rao