Why is St. Anthony called the St. for lost and found?

A student who left the order stole St Anthonys' book of Psalms that he taught from it had all his notes and comments in it.  He prayed it would be returned and it was returned and the student reinstated.

The story took on many twists and turns the more it was told and so there are different versions. 

Lady Darko

Patron Saints have been allotted to all manner of ailments and various trivia.

For example; Against stiff necks - St Ursicinus of Saint-Ursanne

                   Against chiblains -   St Genesius of Arles

                   Against caterpillars - St Magnus of Füssen

There are probably Patron Saints for bleeding piles and flatulence if you search the indexes.

http://www.catholic-forum.com/saints/patron00.htm

Anthony of Padua was sainted in 1261 almost immediately after his death.  He was noted for his doctrine:

"A word fitly spoken is more forcible than any army.  We know the Lord, we know His reasoning.  Let us act in His stead for the good of all mankind."

Anthony is the patron saint of American Indians; animals; barren women; Brazil; elderly people; faith in the Blessed Sacrament; fishermen; Franciscan custody of the Holy Land; harvests; horses; lost articles; lower animals; mail; mariners; oppressed people; poor people; Portugal; pregnant women; seekers of lost articles; shipwrecks; those who have suffered starvation; sterility; swineherds; Tigua Indians; travel hostesses; travellers; watermen; zooligists.

Anthony also represents seekers of the truth and philosophers.  The last of his ministries became the most important as they caused the Franciscans to become far more important in the formulation of official policy through the Catholic Church.