These three books were purchased many years ago and I don’t think were ever used. I’ve had a scan through them and can’t see any evidence of writing or other indications of use. There is a tiny stain to the back cover of book three which must be from contact with other items on the music book shelf. I think they would be suitable for grade 1-3 pianists. I’ve taken photos of some of the pages as examples of the difficulty. This is a clean, smoke free home!