Garbage World (1967)
The Gas (1968)
The City Dwellers (1970)
     aka Twilight of the City
Planet of the Voles (1971)
The Power and the Pain (1971)
The Image Job (1971)
Outdoor Survival (1976)
Sweet Evil (1977)
Love's Savage Embrace (1981) (writing as Charlotte Prentiss)
Double Delight (1983) (writing as Aston Cantwell)
Tease for Two (1983) (writing as Aston Cantwell)
Less Than Human (1986) (writing as Robert Clarke)
Free Zone (1988)
Children of the Ice (1993) (writing as Charlotte Prentiss)
People of the Mesa (1994) (writing as Charlotte Prentiss)
Children of the Sun (1995) (writing as Charlotte Prentiss)
Protektor (1996)
The Island Tribe (1997) (writing as Charlotte Prentiss)
The Ocean Tribe (1999) (writing as Charlotte Prentiss)
Loose Canon (2001)

Highway Sandwiches (poems) (1970) (with Thomas M Disch, Marilyn Hacker)

New Worlds 6 (1973) (with Michael Moorcock)
New Worlds 7 (1974) (with Hilary Bailey)

Who Writes Science Fiction? (1976)
     aka The Dream Makers
Micromania (1984)
How to be a Happy Cat (1986)
When You Can Live Twice as Long, What Will You Do? (1989)
Anarchy Online: Netsex / Netcrime (1996)