Translation:The books were printed in Canada and Iceland.
Many languages make this distinction. Often along the lines of "the country" vs "the landmass". Meaning you would (in german for example) say that a certain tree grows ON Japan (meaning the islands) but would say that Pro Wrestling is hugely popular IN Japan the state. Now with the book the question is open where thr focus should be and I would argue both prepositions to technically work. It's either printed IN Iceland the country or ON Iceland the island.
Books have never been 'pressed'. You're mistaking the archaic concept of a printing press, where the LETTERS are pressed against the paper, with the way that books are PRINTED today. Granted, it's confused by modern printers still occasionally being colloaquially referred to as 'presses' but records and flowers are pressed, books are printed.