Dogs can be trained to assist people.
This article is Copyright 1997 by Cindy Tittle Moore, firstname.lastname@example.org. It may be freely distributed on the Internet in its entirety without alteration provided that this copyright notice is not removed. It may NOT reside at another website (use links, please) other than the URL listed above without the permission of the Author(s). This article may not be sold for profit nor incorporated in other documents without he Author(s)'s permission and is provided "as is" without express or implied warranty.
Please note that while legally speaking, therapy dogs are NOT "service dogs" and NOT entitled to the same benefits that service dogs are (entrance to any public building or transportation), I have included them in this document as a related function for dogs. As you read this, please keep in mind that according to the American Disabilities Act (federal) any dog assisting a person with a disability is considered a service dog (exclusive of therapy dogs). Service dogs are entitled to freely access buildings and transportation (buses, trains, planes). Proof or certification is not required although many organizations that train service dogs give their handlers some sort of ID for their dog.
I have briefly described various "types" of services dogs and listed resources (books, organizations) for each. I have in addition profiled several specific organizations to give you a further "feel" for how these groups work.