A subject, no matter how limited it may be, is not a thesis. The thesis of an essay has two main functions: 1) delimit the subject of the work; 2) clearly state the author’s purpose in writing on that particular subject. The best thing is to formulate your thesis in the introductory paragraph of your essay. Thus, you can clearly expose from the beginning the central idea that you will defend and prove throughout the text.
A thesis is what you – and no one else but you! ─ You mean about the subject you decided to try in your essay. It is the idea or point of view that you will defend and test throughout the essay.
Your thesis is expected to invite a reaction, a debate. That is why it is very useful that you conceive it as a problem, that is, as a matter that needs clarification or something that requires a solution.
After reading The Lizard of Tomes, you may want to write about how the novel criticizes the Spanish society of its time. Thus, “social criticism in El Amarillo de Tomes” is your theme. What you say about that subject will be your thesis, which you must present explicitly in the introduction of your essay. Keep in mind that a thesis usually has more than one sentence. Usually, a good thesis has three to five sentences.
“One of the most outstanding features of the picaresque novel El lazar de Tomes is his keen criticism of Spanish society of the sixteenth century. Since Lazar, the protagonist of the work, lives outside the social norms commonly accepted, can observe the society that surrounds him with the sufficient distance to identify their evils, their vices and their problems. However, these characteristics alone would not be enough to make an effective social critique. In addition to presenting Lazar as a marginal character, the author had to choose a very particular literary resource: autobiographical narrative in the first person. If he had not chosen this type of narration, the author would not have been able to relate the individual story of Lazarus to the classist, corrupt and hypocritical society in which the child had to live. “