Introductions

Scott's Quick Core War Guide by Scott Manley provides complete beginners with a brief introduction to Corewar.

In May 1984, A.K.Dewdney introduced Corewar in Scientific American's Computer Recreations column. Along with D.G.Jones, Dewdney produced the original Core War Guidelines.

Greg Lindahl has written an introduction to Modern Core Wars.

Corewars for Dummies is a short introduction by John K. Lewis.

Redcode Tutorials

The Beginner's Guide to Redcode by Ilmari Karonen covers the basics of programming ICWS'94 Draft Redcode.

Mark Durham's Introduction to Redcode covers programming with the older ICWS'86 and ICWS'88 standards.

Strategy Guides

Introduction to Art in '88 by Wangsaw Mintardjo explains strategies including replicators, scanners and vampires.

My First Corewar Book by Steven Morrell contains two chapters - Chapter 1: Imp-Rings and Chapter 2: Stones.

Anatomy of the Scanner: a Basic Introduction is a guide to implementing effective scanners. Also available as plain text.

Lukasz Grabun has written the first two chapters of the Book of stones.

Reference

The Corewar Bibliography is a thematic index to Corewar articles.

The Core War FAQ and Glossary.

Since A.K.Dewdney introduce Corewar, Redcode has been revised a number of times. The most recent and popular dialect is version 3.3 of the Extended ICWS'94 Draft. Version 3.2 of the ICWS'94 Draft is available as HTML.

Misc

[Polish] Wojny Rdzeniowe is the home of Lukasz Adamowski's Polish tutorial.

[Hungarian] Csaba Biró has a Corewar tutorial in Hungarian.

John Everitt has converted many Corewar documents to PDF.

[German] Sascha Zapf is the author of the Handbuch für Einsteiger.

Wikipedia has an entry for Corewar.

Steve's Guide for Beginners - Steve Bailey's serialised guide for beginners. sgb.zip (28K) contains all 13 issues.