We don't encourage the reading of abridged editions. But, understanding that some parents want to expose their kids to great stories before they're old enough to read the real thing, there are a few collections we've agreed to offer used. All the titles below are massively abridged versions of classic novels and short stories, usually illustrated, and re-written to appeal to less advanced readers.
The problem with abridged books is that they aren't really the original books at all. Sure, the main plot points are there, but classics are more than just bare bones plots; part of what makes a book great is the quality of the author's expression, the wit and grace he or she uses to tell their tale. An abridged or heavily edited version always demolishes the poetry of the original and presents classic stories as simple bulletpoint collections of incidents.
That said, if you intend to have your kids read the original later on, these could provide a decent introduction to provide some familiarity before jumping into Great Expectations or The Iliad. Sometimes reading the classics can be confusing during the first few encounters, and having some knowledge of the general plot, characters, and theme beforehand can be useful (though remember that, in an abridgement, you're getting the editor's interpretation of the theme rather than the theme itself).
With all that said, the abridged classics we have in stock are listed below. Some of them are valuable for their illustrations alone (particularly the Little Unicorn books, with full-color pictures by the Brothers Hildebrandt) or their value as collector's items, but we've priced all of them affordably. We would caution, however, if any of your literature-loving friends come over, hide these volumes in the basement.