matching covers 

1. Dune

1973 printing

no internal personal marks or stamps

2. Dune Messiah

1973 printing

tiny old co-op sticker inside

3. Children of Dune

Dec 1980 copy

4.  Heretics of Dune

First NEL PB March 1985

Plastic covered

all in good condition for age, see images for more detail

Tracked shipping or collect from Roundabout Books Leura (The Blue Mountains) NSW 2782