How can a summary of Upton Sinclair be connected to his most famous work?

The most overwhelming fact about Sinclair's life was that
he started out a Socialist thinker and followed this throughout his life.  Sinclair
believed from an early age that the answer to the condition of the modern setting was to
embrace a Socialist approach to modern consciousness.  This theme is present in many, if
not all, of his writings.  This level of commitment to the cause is something worthy of
note.  Throughout his professional life and successes, Sinclair never lost sight of this
vision.  It helped him found a chapter of the American Civil Liberties Union and
continue to use his craft of writing to offer Socialist critiques of the modern nation. 
This is best seen in his work, The Jungle. The work highlights the
trials of a Lithuanian immigrant, Jurgis, who is struggling with his belief in the
American dream.  Jurgis recognizes, as the reader does, that the fault is not as much
with him, but with a vision of success where few succeed and even fewer are in control. 
In the composition of The Jungle, Sinclair was able to bring
significant attention to food preparation and the basic idea that capitalism in America
had created, in a sense, "two Americas" with one that possessed power and one did not,
as well as the need to rectify such a predicament.