"Being and Time" by Martin Heidegger,1927

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The world,existentially and phenomenologically understood,
is a region of human concern ;
man is being-in-the-world,in that by participation and involvement the world becomes constitutive of man's being.
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Man has being in an environment ;
and his world is a world he shares with others.
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Man is a creature of concerns ;
in relation to environment,his concerns are practical ;
in relation to the communal world,his concerns are personal.
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The three fundamental features of man are :
factuality -he is already involved in the world-,
existence-iality -he is a project and a possibility,that which has been,but also that which can become-,and
fallenness -he has the tendency to become has a mere in the world,failing to make the most of his possibilities because of gossip,curiosity,and ambiguity-.
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Through anxiety man encounters nothingness and becomes aware of his finitude and the necessity of death ; but through resolution man,who moves in time from past to future through the present,appraises himself,chooses with the whole of his being,and thereby achieves authentic existence.
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