tryptamine \ 'trip-ta-,men \ n. [tryptophan fr. tryptic, fr. trypsin, fr. Gk. tryein, to wear down (from its occurrence in pancreatic juice as a proteolytic enzyme) + amine fr. NL ammonia] 1: A naturally occurring compound found in both the animal and plant kingdoms. It is an endogenous component of the human brain. 2: Any of a series of compounds containing the tryptamine skeleton, and modified by chemical constituents at appropriate positions in the molecule. TiHKAL (Tryptamines i Have Known And Loved) is the continuation of the Shulgins' earlier book, PiHKAL (Phenethylamines i Have Known And Loved). Let's get right to it - these books are about drugs and their potential positive uses. Drugs used not simply for entertainment and recreational properties (though that is a nice side effect), but for their mind expanding and self discovering properties. Any serious psychonaut will want to put this book on their reading list. While we are not qualified to provide you with a chemistry lesson, the tryptamines discussed in this book differ from the phenethylamines in that the carbon-carbon-nitrogen chain is attached to an indole group instead of a phenyl group. Compounds/drugs that you may recognize that fall in to the tryptamine category include serotonin, LSD, psilocybin, and DMT. TiHKAL is divided into two parts. The first part is a sort of storytelling narrative written in the two distinct voices of "Alice" and "Shura". It is written as fiction, but the reader is assumed to understand that these are real accounts where the names have been changed to protect the innocent. TiHKAL is less of a "love story" than PiHKAL, and reads more like a series of memoirs and essays. The second part of the book contains recipes, dosages, lab notes, trip reports, and reflections on the use of over 50 specific tryptamines. Several of the compounds described are common recreational drugs, but several were created specifically for experimentation by Alex Shulgin who just happens to be a well known chemist. While the Shulgins obviously take a pro-drug stance with this book, they are not afraid to tell you of their negative experiences, nor is everything described is a dry scientific language. Descriptions such as "weird-ass shit" are not uncommon, and quick notes such as "Never again." are seen. Bad side effects such as intense tinnitus, vomiting thick bilious mucus, and blackouts are just as common as the positive effects of euphoria, opening doors to the psyche, altered states, and pleasant visions.