An Upcoming Book Club Read for September: Republic

I recently joined the Philosophy Books Club on Goodreads and the group is planning on reading Republic by Plato. I've seen this book titled as both The Republic and also as Republic, does anyone know if there is a reason for the difference?

I've never read this and I think it would be interesting to see what it is all about. The funny thing is I don't really read a lot of philosophy books but since I was invited to join this group, I figure this would give me a chance to read more of them.

This is the edition (that I surprisingly already had) that I plan to read:

Book: Republic by Plato with translations by Benjamin Jowett

Description:

One of the greatest works of philosophy, political theory, and literature ever produced, Plato's Republic has shaped Western thought for thousands of years, and remains as relevant today as when it was written during the fourth century B.C.

Republic begins by posing a central question: "What is justice, and why should we be just, especially when the wicked often seem happier and more successful?" For Plato, the answer lies with the ways people, groups, and institutions organize and behave. A brilliant inquiry into the problems of constructing the perfect state, and the roles education, the arts, family, and religion should play in our lives, Republic employs picturesque settings, sharply outlined characters, and conversational dialogue to drive home the philosopher’s often provocative arguments.

It has been said that the entire history of Western philosophy consists of nothing more than "a series of footnotes to Plato." Vastly entertaining, occasionally shocking, and always stimulating, Republic continues to enrich and expand the outlook of all who read it.