The Visual Components of a Psychedelic Experience
This is a comprehensive review of common visual effect categories resulting from the ingestion of psychedelics. Each entry includes a description, the intensity of the trip during which these visuals usually appear (rated out of five), and really accurate pictures recreating each effect (which you can see over there to the right). He's made a really thorough survey and does a great job describing each type. This is by far my favorite post on his site. If you read nothing else of his, read this.
The Mental Components of a Psychedelic Experience
Like in the last link, he describes many types of psychological effects that psychedelics can cause, to help you understand what to expect. Equally valuable as the last one, but without the pretty pictures. :)
His visual representation of what it is like living with HPPD (Hallucinogen Persisting Perception Disorder).
Drug Induced Happiness vs Genuine Happiness
A really vital distinction. Many drug users don't understand the difference and therefore end up abusing the euphoric potential of certain substances, while many people with an anti-drug stance believe that drugs completely prevent true happiness.
How to easily avoid freaking out and having a bad trip
He offers both general statements that quell most neophyte psychonauts' anxiety ("you are not dying!") and also states his opinion on how to create the best set and setting.
Let's all begin testing the existence of DMT entities
His (admittedly cannabis-produced) idea of how to verify or disprove the actual existence of the alien entities often encountered during DMT trips.
Simple Mushroom Growing Technique
A basic but thorough guide. In my opinion, better-organized and more informative than the classic Erowid guide.
Simple DMT Extraction Technique
For all those eager to have the legendary DMT experience. No previous chemical expertise needed.
The Subjective Differences Between LSD, Mushrooms, and Ayahuasca
The first article I read from his site, and definitely one of the most insightful. I have only done mushrooms once, and ayahuasca never, and I never really assumed that they were too much different in quality. However, this guy disagrees and lays out for us the specific differences and similarities in a variety of categories. Also contains lots of pretty pictures!
Simple Ayahuasca Brewing Technique
Another really great guide.