Complex sentence: The second oldest book dedicated to Tonga was by William Mariner adopted son of Finau'Ulukalala which was published in 1817 about his experiences durng the years he was with' Ulukalala (1806-1810).
Split into simpler sentences: The second oldest book dedicated to Tonga was by William Mariner, adopted son of Finau'Ulukalala which was published in 1817. Mariner descriped his experiences durng the years he was the adopted son of' Ulukalala (1806-1810).