Spiney Spider

I need to know now what kind of spider this is and where it lives. I might start pursuing a career in biology if for no other reason than to be able to identify creatures like this so that I might be able to avoid them.

My work on this blog has let me know that this world can be an ugly place, and that I am fortunate to live in a relatively benign region of California. At least I don't go outside to find these spiders clambering about my yard.

Thanks for the great photo, Raju.