Stumped about stumpwork

So I'm perusing the books over at Crafter's Choice and I'm seeing these books on stumpwork. What is stumpwork? It looks like crewel embroidery to me. Is it the same as crewel or is it something altogether different? I'd so appreciate it if anyone could fill me in. :)

By the way, Isabelle is home and she LOVES Annabelle!!