Original factory instruction manual-original hard covers present but protected by loose brown paper sleeve by a previous proud owner. Size 10" X 7.25". This is a wonderfully comprehensive manual, with many illustrations.Engine dismantling & also other components is covered, electrical-the lot, in fact. It is a joy to study even if you dont actually own a Riley Nine. Model variants covered are Mark 4 "Plus & "PLus Ultra". NOTE-photos of additional pages available if interested.