Could you make a bookcase out of it and still allow easy access for entry to all rooms?

Truly can't see what you mean...maybe that's because you don't need to do anything.

Could you be more specific? Show better pictures?

Thank you so much for the quick reply.

Here are s few more picture that I hope illustrate my problem. I need a better definition of each space but also to show continuity between the living to the TV area. The posts that were create somehow confusion. It feels something is missing there.

The corridor does not bother me. Are you opposed to hiring a designer? I love what you have for the living room but there is wasted space on the other side. One thing I dislike about open concept houses, and your house is lovely, is the fact that arranging furniture can be more difficult. Also, I would consider the tv room as part of the living room and decorate with that in mind. Similar to how a dining area is decorated to go with a kitchen, when they are open to each other. It all must flow.

If the center beam cannot be removed (weight bearing) then I would make "lemonade out of a small lemon" :-)
To echo the glass at your stairway, install between one of the posts a clear glass waterfall fountain or if that isn't possible, a glass and crystal bead floor to ceiling art or clear leaded-glass design, or seeded glass panel (something to keep light flowing). This will of course make your other opening feel smaller but it might make what you are describing feel better.
A tall, ficus plant (selectively pruned to make it light and airy) might make a nice addition to marry the two rooms.

IMO you need nothing there not every space in a home needs decor sometimes less is definately more