HITW- I'm not sure how successful it'd be, but I'd recommend looking in second-hand bookshops in the area where it was published/where your great-great-grandfather lived. One of our lecturers has managed to locate one or two self-published books this way. Do you know if enough were printed so that a copy was sent to the British Library? Otherwise W H Smiths used to do a rare books search service, although I don't think it was ever very helpful. Otherwise this is a database of hundreds of different independent and second hand bookshops which has sometimes helped me:
*clicky*