If you're considering a dog, there are two excellent books worth consulting. Paws To Consider by Brian Kilcommons and Sarah Wilson offers unusually clearheaded advice about the reality of dog ownership, providing good information to help you decide what kind of canine will fit into your lifestyle best. A Buyer's Guide by Michele Welton is also a terrific guide for people interested in selecting the right breed. Speaking of breeds, I am continually amazed at how many people aren't aware of the health problems caused by the breeding practices necessary to create purebred dogs or cats. The advantage of purebred animals is that they have predictable dispositions and sizes.
Mutts are usually healthier.
But getting a mixed breed, especially as a puppy, is a lot like buying a used car. You won't know exactly what you've got until you've owned it for a while. One of the larger ones, the Humane Society of Greater Akron, makes an effort to match prospective owners with animals they can live with. The counselor reviews each person's lifestyle to make sure that they either own their own home or have a landlord who permits pets. They ask about allergies, the age of children in the home, and the plans to provide care for the animal day and night.