The Philosophy in 90 Minutes series, written by Paul Strathern, is a series of short introductory biographical overviews on well-known philosophers, set in brief historical context, along with brief impressions of their philosophies.
The books are also produced in audio format; read by narrator Robert Whitfield.
The series’ intent is to "write about the philosophers' lives, [while] adding in a few of their ideas"[1][2][3] The books and audio presentations are considered to be outlines of the given philosopher.
Interesting anecdotes about the subject are pervasive, and lines are quoted from published works in "an epigraphic style".
[1][3] Some titles in series are: Socrates, Plato, Aristotle, Confucius, Machiavelli, Descartes, John Locke, Hegel, Heidegger, Hume, Kant, Marx, Rousseau, Schopenhauer, Spinoza, Kierkegaard, Borges, and Nietzsche.