The Anarchist Library is a great archive of free books and essays on the topic of Anarchism. Some newer books won't be available there due to copyright (thanks Capitalism! /s).

Here's some recommendations to get you started:

• Demanding the Impossible: A History of Anarchism, Peter H. Marshall
• The Conquest of Bread, Pëtr Kropotkin
• No Gods, No Masters: An Anthology of Anarchism, Daniel Guérin
• Anarchism: A Very Short Introduction, Colin Ward
• Mutual Aid: A Factor of Evolution, Pëtr Kropotkin
• God and the State, Michail Bakunin

*Dear mod: I don't think there's any copyright concerns with the linked texts, but if there is I'll remove the direct links. I only added them because the search function on the archiveis a bit borked, so it can be hard to find what you're looking for.