Is there a way to add a word to an existing textbook list? For example, in the list for the textbook I am using, it seems to be missing one of the vocabulary words. The word exists in an earlier lesson, with a different meaning, so perhaps it isn't added for that reason (perceived as a duplicate?). As I haven't studied that lesson yet, though, I'd like to add the word to this lesson. Can that be done??

A published list can not be edited, but you can remix it and then add a word, I guess. See this in the help section:
http://www.skritter.cn/faq#publishing

Or you could just add the particular word to the queue http://www.skritter.com/vocab/queue

Yup, above posters have it. Please also let me know which word it is and where it should go in the lesson, so I can fix it.

Thanks, everyone! I have added the word to my queue, and Nick, I emailed you with the specifics. Very nice!