A good reference/info book?

[buscador]

Hi guys (and gals)

I currently collect AK's and it's variants. I would like to get into AR-15's but I really don't know much about the different models. Can anyone recommend a good resource/info book on this family of rifles? Something with lots of info and pics of the different models produced.

Thanks
buscador

[recon]

Try this for starters!
www.deltapress.com