Books
Below is a list of books which can provide a good introduction to Buddhism.
General Buddhism
The Long Discourses of the Buddha Translated by Maurice Walshe: Wisdom Publications
The Middle Length Discourses of the Buddha Translated by Bhikkhus Nanamoli and Bodhi
What the Buddha Taught by Walpola Rahula, ISBN 0-8021-3031-3, Grove Press
Old Path, White Clouds by Thich Nhat Hanh, ISBN 0-938077-26-0, Parallax Press
Zen Buddhism
Zen Philosophy, Zen Practice by Thich Thien An, ISBN 0-913546-33-X, Dharma Publishing
The Sutra of the Sixth Patriarch
The Works of Dogen Zenji
Any of the Transmission of light Documents