Actually what you are referring to is not spam. O'Reilly are not spamming you if they are writing to you directly. In that case everybody who writes to someone without having met the person first would be classified as a spammer. Actually now that I think of it - this comment I'm writing to you now could be spam!

Of cause O'Reilly should respect your whiches not to be contacted if you reply to the e-mail in question. You don't write if you have actually tried that? - you said you just deleted it?