Complex sentence: He had advanced social views: he was an atheist (he wrote a book called "Analysis of Religious Belief") and an advocate of birth control (as was his wife)-his position on this subject cost him his position as an MP.
Split into simpler sentences: He had advanced social views: he was an atheist (he wrote a book called "Analysis of Religious Belief"). He was an advocate of birth control (as was his wife)-his position on this subject cost him his position as an MP.