System of Logic (1843)[T]he most scientific proceeding can be no more than an improved form of that which was primitively pursued by the human understanding while undirected by science. (System, VII: 318)
Viewpoint was that inductive reasoning is improved upon by self reflection, taking existing knowledge, forming hypothesis for further refinement.
Mill’s 4 methods of induction: Method of Agreement, Method of Difference, Method of Residues, Method of Concomitant Variations.
Principles of Political Economy (1848)“Since the state must necessarily provide subsistence for the criminal poor while undergoing punishment, not to do the same for the poor who have not offended is to give a premium on crime.”
Mills proposed that economics is separate from the laws of nature, therefore men could alter it for the overall good of others. This book recounts his thoughts on economics over his lifetime, even as early as age 13. He also extends details of his life through the bibliography section.
On Liberty (1859),It is proper to state that I forego any advantage which could be derived to my argument from the idea of abstract right, as a thing independent of utility. (Liberty, XVIII: 224)
On Liberty discusses his views of a representative democracy and the development of liberty. He discussed 3 types of liberty: liberty of thought and opinion, liberty of tastes and pursuits, and freedom to plan our own lives.
Utilitarianism (1863)“happiness is the sole end of human action, and the promotion of it the test by which to judge of all human conduct” (Utilitarianism, X: 237).
His next book discusses utilitarianism in detail, where decisions should be made based on the overall greater good of society vs. personal gain or loss. He goes into detail on how individual liberties should be given but ones actions should be what is best for society and an individual's duty to promote happiness.
Macleod, Christopher, "John Stuart Mill", The Stanford Encyclopedia of Philosophy (Summer 2020 Edition), Edward N. Zalta (ed.), URL = https://plato.stanford.edu/archives/sum2020/entries/mill/.
Priest, John, "Philosopher of the month: John Stuart Mill [timeline]", Oup Blog. April 9th 2017. https://blog.oup.com/2017/04/john-stuart-mill-timeline/