The book Zig Zag Zen is about the connection between psychedelic drugs and Buddhism.
Drugs are always a controversial subject, and in my view it's never as simple as them being good or bad, despite what the "War on Drugs" people tell us.
My own personal views on this aren't completely clear, but I found the passage below food for thought. I'm interested in hearing your comments!
So how do we express and characterize the relationship between psychedelics and Dharma practice? The conventional answer, offered by many once-tripping Buddhists, is that drugs can "open the door." Without much work or knowledge on the part of the user, psychedelics can crack open consensus reality, expand identity beyond the confines of conventional self, induce ego-death, and unveil the connection between mind and the totality of the real. However "unauthentic" these experiences may be judged to be, many people respond to them by turning to Eastern practice in order to extend, comprehend, and deepen their insights. Once their practice has stabilized and opened up, many of these people abandon drugs as needless or even harmful distractions. In this view, spiritual practice becomes something like the liftoff of Apollo 11. Drugs point you toward the moon of enlightenment, and somewhat violently thrust you away from the gravity of consensus reality. Having done so, they can then be abandoned like the early stages of a rocket. Or as Alan Watts quipped, "Once you get the message, hang up the phone."