PIHKAL and TIHKAL

PIHKAL and TIHKAL are the two landmark books by the chemist Alexander "Sasha" Shulgin and his wife Ann Shulgin that document, compound by compound, a large family of psychoactive molecules Shulgin first synthesized and evaluated. They are foundational references for modern psychedelic science and harm reduction. This article is the Library's map of them — what they are, how they're organized, and where to read them — following the same approach the Library's Hierophant uses for Sacred-Texts and Theoi: we do not reproduce the copyrighted text; we index it and link out to where it lives legally.

PIHKAL (1991) — "Phenethylamines I Have Known And Loved." Covers the phenethylamine family (the 2C-x series, the DOx series, the mescaline and MDMA relatives, and many others).
TIHKAL (1997) — "Tryptamines I Have Known And Loved." Covers the tryptamine family (DMT and its relatives, the psilocin/psilocybin group, and others).

How the books are built

Each book has two parts:

Part One — an autobiographical and philosophical narrative (in PIHKAL, a lightly fictionalized memoir of "Shura" and "Alice"; in TIHKAL, essays spanning chemistry, law, and spirituality). This half is fully copyrighted and is not freely distributable.
Part Two — the systematic chemistry: one entry per compound. This is the part researchers cite. The Shulgins placed this second half under terms that permit free non-commercial reproduction, which is why it is mirrored online.

The Shulgin Rating Scale

Shulgin recorded the subjective intensity of each experience on a simple qualitative scale (described here in our own words):

minus (−) — no effect detected.
plus/minus (±) — a threshold: something is felt, but it could be imagination.
plus (+) — a real but light effect; the compound is clearly active, its character not yet obvious.
two plus (++) — clearly and unmistakably active; the full character shows, and the person can still choose to engage with the world or the experience.
three plus (+++) — maximal intensity for that compound; fully absorbing.
four plus (++++) — a rare, separate category: a peak / transcendent state, not simply "more" than +++.

The scale also tracks dose (an active range in milligrams) and duration (onset and total length) — the factual harm-reduction data the Library does surface.

How the Library treats this material

Following the Hierophant / link-out model:

We map and cite; we do not paste. Reproducing the books' text verbatim would be a copyright violation. Our contribution is the index, the context, and our own glossary written in our own words.
Harm-reduction reference, not a manufacturing manual. The Library serves dose ranges, duration, effects, interactions, contraindications, testing, and set/setting/aftercare — the information that keeps people safer. Consistent with its scope, it does not host synthesis or extraction routes; for the full chemistry entries we point to the licensed mirror.
Un-gated. This is reference and education for adults, presented plainly and without gatekeeping.

Where to read the full entries

The Part-Two chemistry entries are hosted, with the Shulgins' permission, at Erowid:

PIHKAL: erowid.org/library/books_online/pihkal
TIHKAL: erowid.org/library/books_online/tihkal
Erowid's compound vaults also carry dose/duration/effect/interaction summaries and experience reports: erowid.org

The complete books (both parts) are published by Transform Press.