Complex sentence: The explorer Ferdynand Ossendowski wrote a book in 1922 titled "Beasts, Men and Gods" in the book Ossendowski tells of a story which was imparted to him concerning a subterranean kingdom which exists inside the earth.
Split into simpler sentences: The explorer Ferdynand Ossendowski wrote a book in 1922 titled "Beasts, Men and Gods". In the book, Ossendowski tells of a story which was imparted to him concerning a subterranean kingdom which exists inside the earth.