Welcome to the F&G board, Plutolover!
Plutolover, if your backyard is that steep, I would strongly recommend you hire a landscape architect to give you some ideas on how to deal with it. They will charge you a fee of course, to draw up a plan, but that doesn't mean you have to have them do the work. You can use their suggestions, and do the work on your own, if you choose. There may be special regulations or an ordinance in your municipality regarding steep slopes and re-grading, and if so, they will have that information.
Do other houses in your area have the same landscape challenge? If so, check out what they've done. There may be some solutions that appeal to you.
Constructing rock garden pockets, terracing, and even building retaining walls (rather costly), are all options open to you. A professional can advise you on what's best for your unique situation.
In the meantime, you might want to do some reading on steep slope landscaping.
The following links might interest you!
~Landscape Challenges~
~Slope Problems - An Uphill Battle~
Kim
