Spelt is a close cousin of wheat. It has been used in Europe since about 5000 B.C. but has only recently gotten popular in America as a delicious and healthy grain for people to use like they use ordinary wheat.
Spelt flour has a somewhat nuttier and slightly sweeter flavor than whole wheat flour. Since spelt is easier to digest, in can often be tolerated by people with wheat sensitivities; however it does contain some gluten and cannot be used for people with gluten allergies.
You can use it to make bread and it turns out almost as well as with wheat, although it doesn’t have as much gluten as hard wheat so it probably will not rise quite as high.