TSAR - TSAR

I understand the placement of the separation in this novel, but why call them separate books? it's all the same story; however, each book can be summed up into one basic idea:
a relationship is introduced (Book I)
relationships are broken (Book II)
things are mended or left behind (Book III)

until just now, (literally just now, 11:22 PM on Thursday, 12 August)I never really understood the connection to the title. Why "The Sun Also Rises"? Why "Also"? I never understood why that was important. I mean, "The Sun Rises" was just too plain for Hemingway or something? But no, I've now interpreted it as more of a way to move on. just as relationships, friendships, people, places, things, events, etc, rise and fall, so does the sun. The sun, the source of all life, goes through the same phases as the world as a whole does. the sun goes through the same rise and fall as a human being does. not literally of course, but we never see the Earth move. it's the Sun that moves.

the whole book, in telling the seemingly unimportant tale of this group of friends, creates an extended metaphor, conceit, even, with the sun, the cycle of life. the rise and fall, rage and grace, depression and elation that govern the whole world and the steps taken to either mend or leave behind these pieces. the very last line of the book,

"Yes, isn't it pretty to think so?" (p. 251)

emphasizes this fact in a way that is profound, yet simple. it's human nature to think that everything is fine and will work out well, but the fact is that not everything will happen as planned, but even when things look dark,

the sun also rises.