What specific fair and balanced non-polemic books and articles should I read in order to address the following question: Is there some similarity, and if so what is it, between (X) the stated economic principles of communism in reducing economic inequality in society, and (Y) the principles of movements in the US presently advocating the reduction of economic inequality in the US?
This is an interesting question because it requires you to know the difference between something "polemic" and "non-polemic." Let's take a look at the definitions and then at a few books that might point you in the right direction.
The word stems from the idea of two magnetic "poles" being completely opposite and, therefore, something polemic would inspire great debate and controversy. Something polemic, then, would be very controversial and often even very biased; therefore, something non-polemic would be just as you say in your question "fair and balanced" as well as fairly non-controversial in regards to ideas.
The great irony of your question is that "principles of communism" as well as "reduction of economic inequality" IN THEMSELVES can be seen as polemic and controversial! What NOT to read: Animal Farm. :-) Therefore, in the spirit of being both non-polemic and non-controversial, I think it's very important to take the very, very polemic term "Communism" out of the equation and focus on economic inequality instead. I also want to focus only on very current books in order to give you some of the most recent information. THUS, here are the two main books I suggest: Capital in the 21st Century and Inequality and Instability.
First, let's look at Capital in the 21st Century by Thomas Piketty. Basically, this is the history of inequality (in regards to income) only in regards to the United States and Europe since the 1700s. Here is Piketty's catch-phrase:
You know, if two-thirds of this growth goes to the top 1 percent, it’s not clear that this is a good deal for the rest of the population.
In trying to be as non-polemic as possible, Piketty uses many charts and bits of tax data that he could find, even going back to the industrial age! He has an interesting theory: that wealth grows faster than economic output. BUT beware a bit of controversy in suggesting a global wealth tax! Here we see that almost no book on the subject of inequality can be completely non-polemic
In regards to more global income inequality, my first choice would be Jamie Galbraith’s Inequality and Instability. It is a fairly new book and, due to it's title, is often picked up by readers hoping for a polemic slant; however, this book is anything but polemic! It features a group of essays that use prominent statistics to assess income inequality in society. Further, it puts America in to the context of the world:
There are practically no jobs to be had in the winning sectors…the American economy became leveraged, in such a way that its performance as a whole came to depend on the possibility of a very small number of people becoming very rich in very limited lines of work.
There is also a lot of "income inequality" discussed where Latin America is concerned. It turns out that Galbraith believes that finance is what drives inequality.
In addition to the book above, I would suggest reading Nickel and Dimed, which is a personal and non-fictional account of trying to live in the real world of minimum wage earners in America. Because it is non-fictional (although it does have a definite slant), and because the stories in it are very true, there is much about it that is non-polemic and worth the read.
When someone works for less pay than she can live on -- when, for example, she goes hungry so that you can eat more cheaply and conveniently -- than she has made a great sacrifice for you, she has made of a gift of some part of her abilities, her health, and her life.
In conclusion, I'll suggest an interesting read about Communism (against my better judgement due to the "non-polemic" request of your question). Try reading The Secret World of American Communism which has much to say about the very beginning of Communism in the United States and how it began with a VERY non-controversial idea: that it was a political party with a left-leaning slant that wanted equality for black people, good wages for all workers, etc. We actually have a good resource right here at eNotes about that particular book, so you can gain even more information from the link below.