Middlemarch is a book about a pair of bad marriages. The first is that of Dorothea Brooke, the "Saint Theresa" of the above passage, who is ardently devoted to religion and to charity, and hopes to marry a man whose wisdom and devotion will help to elevate her spirit. She thinks that the aging, ugly Reverend Edward Causubon is that man:
"He thinks with me, said Dorothea to herself, "or rather, he thinks a whole world of which my thought is but a poor twopenny mirror. And his feelings, too, his whole experience--what a lake compared with my little pool!"
But, as she will learn, Casaubon is not that man--his life's work, a Robert Graves-like "Key to All Mythologies," remains unrealized, an abortive intellectual project that would be useless and meaningless even if he could ever get around to writing the first page of it. Casaubon feels keenly that he is a failure, and Dorothea's devotion to him ultimately only spurs his anger and resentment. Because this kind of plot requires there to be a right man for Dorothea, Casaubon's insecurity is amplified by his fear that Dorothea is in love with his young cousin Will Ladislaw.
The second marriage is that of the young doctor Tertius Lydgate and Rosamond Vincy. Lydgate is an ambitious man, eager to contribute to the world of medicine and with the talent to do so, but he falls for the vain Rosamond, who drives him into debt and derails his hopes. These two marriages act as pillars for the novel, which also contains a handful of side plots concerning the inhabitants of the titular town, but Eliot puts the Dorothea story clearly at the center of the novel. Ironically, Dorothea's poor marriage does elevate her spirit and grow her in wisdom, as she shows when she finally meets Rosamond in the book's final pages:
"Marriage is so unlike everything else. There is something even awful in the nearness it brings. Even if we loved some one else better than--than those we were married to, it would be no use"--poor Dorothea, in her palpitating anxiety, could only seize her language brokenly--"I mean, marriage drinks up all our power of giving or getting any blessedness in that sort of love. I know it may be very dear--but it murders our marriage--and then the marriage stays with us like a murder--and everything else is gone. And then our husband--if he loved and trusted us, and we have not helped him, but made a curse in his life..."
"The marriage stays with us like a murder"--that is wonderfully evocative, and a great example of Eliot's formidable prose and strong characters. Dorothea is intricately realized, but so are the "fringe" characters that populate Middlemarch, like Dorothea's scatterbrained father Mr. Brooke, the lazy but warm-hearted Fred Vincy, and ten or fifteen others. I mentioned in my year-end review that Tolstoy was a big fan of Eliot's, and Middlemarch has that kind of immense Tolstoyan scope but also the kind of fine attention to the peculiarities of character that I associate with somebody like Austen or even Shakespeare.
Eliot sets her story at the historical moment of political argument over the Reform Bill of 1832. The minor figures of Middlemarch talk about it constantly; Will Ladislaw champions it as the editor of a local paper with the patronage of Mr. Brooke, who mulls a candidacy for Parliament. I admit I didn't understand most of the details, but I did glean that the reform in question was the expansion of suffrage, and Middlemarch reflects that in the expansiveness of its depiction of the town. By focusing on such a large cast of characters, Eliot expresses a kind of universal suffrage, as she is interested in capturing the voices of as many people as possible. Reform, too, seems to me to be a central idea: how people seek to reform themselves by seeking wisdom, prudence, and responsibility.
The story of Dorothea knits those two aspects up nicely: she is constantly seeking to be a better person, though she is certainly the best person in the book already. Furthermore, Eliot is deeply interested in the idea that there are unrecognized saints, like Dorothea, whose goodness never gets recognized because it toils in anonymity. Eliot ultimately can't bear to deny Dorothea the happiness she deserves, and though perhaps it would have been bolder to let her remain in selfless abegnation, it's rewarding to see goodness rewarded.