Laurence Yep

The Man Who Tricked a Ghost is a story from third century China, retold by Laurence Yep and illustrated by Isadore Seltzer. In it, a brave young man named Sung is on his way home one night when he encounters a fierce ghost. The ghost says he's on his way to scare a man named Sung. Sung tries to fool the ghost by claiming to be a ghost himself and suggesting that they take turns carrying each other on their backs. Sung tricks the ghost into confiding that human spit renders ghosts unable to change their shape. When they reached town, Sung grabs the ghost and tries to take him to the temple. The ghost immediately transforms himself into a sheep, but the clever Sung quickly spits on him, trapping him in that harmless form forever. He then sells the sheep and becomes rich.
Kids seem to love tales of trickery, and this is a great example. Most of the other folktales I know that have similar themes are African, so I was glad to find one from a different cultural perspective. The clever confidence of Sung helps to keep kids from becoming too alarmed about the ghost, who does appear rather threatening in some of Seltzer's illustrations.
Yep has written dozens of books, including several series, and the best place I found to see all of the titles was at http://www.fantasticfiction.co.uk/y/laurence-yep/. He is probably best known for his Dragon series and his Golden Mountain Chronicles series, both written for intermediate and middle school audiences.