Three Worlds
- A lecture delivered at the University of Michigan, April 7, 1978.
- http://www.tannerlectures.utah.edu/lectures/popper80.pdf

Language and the Body-Mind Problem
- Text of this 1953 paper by Popper, with hyperlinked footnotes and a later note by the author.
- http://www.ditext.com/popper/lbp.html

Against Television
- An interview with Sir Karl Popper, in Italian, with an English summary.
- http://www.mediamente.rai.it/mmold/english/bibliote/biografi/p/popper.htm

Letter from Karl Popper
- Scanned image of a 1992 letter to Kelley L. Ross.
- http://www.friesian.com/ross/popper.htm

Extracts from "The Open Society and Its Enemies"
- Selected passages from this 1945 work, Popper's most well-known.
- http://lachlan.bluehaze.com.au/books/popper_open_society_vol1.html

Prague Lecture
- Speech delivered by Popper in the Czech Republic shortly before his death.
- http://www.lf3.cuni.cz/aff/p2_e.html

From Sir Karl Popper
- Selected correspondence between Thomas Szasz and Popper, between 1961 and 1984.
- http://www.szasz.com/popper.html

Popper on Kantian Concept of War on War
- Text of a 1993 interview giving Popper's take on the contemporary world situation.
- http://ghandchi.com/iranscope/Anthology/Popper.htm

A Realist View of Logic, Physics, and History
- The next-to-last chapter of Popper's 1966 work Objective Knowledge. Contains a concise presentation of his epistemological views.
- http://www.marxists.org/reference/subject/philosophy/works/at/popper.htm

The Problem of Induction
- Text of this key 1953 paper, in which Popper presents the view of the scientific method as a critical, rather than inductive process.
- http://dieoff.org/page126.htm