I am doing some personal research on ideologies that have helped shape the modern age and would like to find literature that encapsulates these ideas from all angles. I live in the U. S., and am familiar with the capitalist democratic system we have, but would like to find literature that holds the same weight as the communist manifesto, but towards capitalism (I am currently reading the communist manifesto). Is this even a possibility given the nature of capitalism?
Literature regarding other ideologies that have held similar influence to these to are definitely a plus! But at the current moment my research is comparing and contrasting Capitalist VS. Communist).
In some way, you could try Wealth of Nations by Adam Smith. It's not really an equivalent, but an often cited book from the time social sciences appeared in its modern form.
I'd say it'll be easier to understand if you decompose the current capitalist democratic system into the parts concerning itself with economics, with law, with philosophy/ethics etc. Capitalism is not an easy term to describe, and discussants often have different ideas of what it means. Read e.g. a book about utilitarianism, an important ethical foundation for common capitalist opinions.
The Communist Manifesto does not encapsulate Communism in any way, in fact the preface to the 1872 edition has Marx saying that multiple parts of it have become outdated already.
If you want to learn more about Communism, it's important to read Das Kapital or at least a good summary of it. Carlo Cafiero for example wrote one in 1879, which was approved of by Marx:
https://www.marxists.org/archive/cafiero/1879/summary-of-capital.htm
The trouble is that the word "capitalism" began in the 19th century as a label for the existing economic system in the UK and similar countries. There was no one advocating for capitalism before it appeared. Certainly some bits and pieces had their advocates at a national level, for example the English parliament passed various Enclosure Acts, but other bits just happened as the result of myriad decisions, like the disappearance of serfdom and the development of much common law.
Adam Smith is sometimes described as the advocate of capitalism but he didn't use the word itself, instead he talked about liberty or natural liberty and justice. Smith was to a large extent someone who described existing economies. He did make some policy recommendations but he was skeptical about the ability of any one to design a whole system. And sometimes he criticised policies of his time that some future Marxists would describe as essential to capitalism (e.g. Lenin), for example Smith opposed European imperialism on moral grounds and also argued that it made the European economies poorer than they otherwise would be. In the 19th century economists in Adam Smith's tradition would talk about favouring free markets or being liberals, and argue for various reforms of existing economies, like free trade and the abolition of slavery.
It's only in the 20th century that people like Milton Friedman or Aynn Rand started defending capitalism in that wording, and that didn't stop them being critical of a number of things the US government was doing. Rand actually wrote a book titled Capitalism: The Unknown Ideal. I think their adoption of the term "capitalism" was driven by the use of it by Marxists. [Edit to add] So note that what Friedman or Rand were advocating under the word "capitalism" could be very different from what Marxists were attacking.
If you want something written with something of the passion of the Communist Manifesto then there's Milton Friedman's Free to Choose, published 1962.
I'd like to add in a word of warning about manifestos and similar literature: it's very easy to create a hypothetical system that works brilliantly and then compare it to the real world in all its messiness. Actually building a real world system is a different matter. It's fascinating to watch Lenin go from a critic on attack mode pre-Russian Revolution to grappling with the real world difficulties of policy post Revolution. When he introduced the New Economic Policy he openly called the Bolshevik's earlier policies a mistake and the New Economic Policy a retreat, a temporary retreat to build up the strength for a final victory but a retreat. I suspect Objectivists would have a similar set of problems if they ever got into power. Milton Friedman was less utopian, he did work for the US government in WWII, but for example when economists came to actually try to reduce inflation they found problems like defining what the money supply actually is.
So I will end by quoting Adam Smith, from his first book, The Theory of Moral Sentiments (1759):
The man of system, on the contrary, is apt to be very wise in his own conceit; and is often so enamoured with the supposed beauty of his own ideal plan of government, that he cannot suffer the smallest deviation from any part of it. He goes on to establish it completely and in all its parts, without any regard either to the great interests, or to the strong prejudices which may oppose it. He seems to imagine that he can arrange the different members of a great society with as much ease as the hand arranges the different pieces upon a chess–board. He does not consider that the pieces upon the chess–board have no other principle of motion besides that which the hand impresses upon them; but that, in the great chess–board of human society, every single piece has a principle of motion of its own, altogether different from that which the legislature might chuse to impress upon it.