Audible has a series of free introductions for 17 works by Charles Dickens. They're written and narrated by David Timson and published by Naxos Audiobooks. They range in length from 20 to 39 min.
FREE -- The Novels of Charles Dickens: An Introduction -- David Timson
- A Christmas Carol -- 29 min
- A Tale of Two Cities -- 25 min
- Barnaby Rudge -- 30 min
- Bleak House -- 28 min
- David Copperfield -- 28 min
- Dombey and Son -- 24 min
- Great Expectations -- 25 min
- Hard Times -- 25 min
- Little Dorrit -- 31 min
- Martin Chuzzlewit -- 24 min
- Nicholas Nickleby -- 39 min
- Oliver Twist -- 27 min
- Our Mutual Friend -- 35 min
- Sketches by Boz -- 28 min
- The Mystery of Edwin Drood -- 32 min
- The Old Curiosity Shop -- 20 min
- The Pickwick Papers -- 28 min