The books the creature, in Mary Shelley's Frankenstein, finds (Lives, Sorrows of Werter, and Paradise Lost) greatly influence the creature. In chapter fifteen of the novel, the creature defines the impact of the books.
They produced in me an infinity of new images and feelings that sometimes raised me to ecstasy, but more frequently sunk me into the lowest dejection.
This ext defined the history of the world for the creature. It was this text which allowed the creature to be introduced to "high thoughts." The text allowed the creature to think about others, outside of himself:
He elevated me above the wretched sphere of my own reflections to admire and love the heroes of past ages.
Goethe's Sorrows of Werter
This text allowed the creature to examine the simpler things in life. It opened his eyes to the domestic sphere and the pain associated with life.
The disquisitionsupon death and suicide were calculated to fill me with wonder. I did not pretend to enter into the merits of the case, yet I inclined towards the opinions of the hero, whose extinction I wept, without precisely understanding it.
That said, although the text opened the creature to different feelings, he still states that the text is above him.
Milton's Paradise Lost
Paradise Lost was the text which most impacted the creature. It was through this text that the creature first realizes how his "father" abandoned him, like God abandoned Satan. This text allows the creature to feel a connection with another being--something he has lacked to this point in his "life." The creature read the text "as a true history," as he read the other texts. He believed the text to be historical and factual in nature. Essentially, the most important idea behind the text was the creature's engagement with another being--given to this point he has felt utterly alone.
Like Adam, I was apparently united by no link to any other being in existence; but his state was far different from mine in every other respect...Many times I considered Satan as the fitter emblem of my condition; for often, like him, when I viewed the bliss of my protectors, the bitter gall of envy rose within me.
In the end, all of the texts opened the creautre's eyes to the immediate world around him. Limited by his "age," the creature lacked basic knowledge about the world, although he was expected to live in it alone. Through the texts, the creature is able to discover certain things about the world and find his place in it--through his relation and understanding.