⓪ He is more interested in English, than in Japanese, literature.
① The feeling of utter remoteness was my first and remains my main impression of this expedition across the Iron Curtain.
= The feeling of utter remoteness was my first (impression of this expedition across the Iron Curtain) and (the feeling of utter remoteness) remains my main impression of this expedition across the Iron Curtain.
② Perhaps the most striking fact about modern science is that, like poetry, it reveals depths and mysteries beyond, and, this is important, quite different from the ordinary matter-of-fact world we are used to.
=Perhaps the most striking fact about modern science is that, like poetry, it reveals depths and mysteries beyond (the ordinary matter-of-fact world we are used to), and, this is important, (it reveals depths and mysteries) quite different from the ordinary matter-of-fact world we are used to.