One way to find out who painted a particular painting is to look for the artist's signature, which is usually located in the bottom right corner of the painting. Most paintings include a signature, monogram or other marking that identifies the artist.
If it is not possible to read the signature on the painting, one recourse is to consult a dictionary of signatures and monograms. These dictionaries are maintained by auction houses and art appraisers and are generally updated regularly. Readers should get the most up-to-date version of the dictionary before attempting to identify the artist of a given piece.
Other resources include consulting employees at local libraries and art museums.