Complex sentence: Alexander Bell Filson Young (1876--1938) was a journalist, who published the first book about the sinking of the "RMS Titanic", called "Titanic", published in 1912 only 37 days after the sinking.
Split into simpler sentences: Alexander Bell Filson Young (1876--1938) was a writer and journalist. He is notable for publishing the first book about the sinking of the "RMS Titanic", called "Titanic", published only 37 days after the sinking.