From the introduction:
Alchemy favors the transmuter. It holds the secrets to immortality, wealth, and power. Many potions feel ego-derived: crystallized ambitions. Other potions deal with substance and shape—the lever by which alchemy moves the world.
Liquids are preferred. Solids are difficult to mix and homogenize. Gases are difficult to contain and quantify. And let's not speak of the fire alchemists.
It is a strange thing, alchemy. Much safer than wizardry, since you merely risk your life, rather than your sanity.
And yet it has it's own quirks. The formulae wander, attending the phase of the moon, or some other, more occult determinant. The constants are not universal.
There are tales of potions failing at times of critical use, as if in revenge for past abuse. And of course, anyone who has seen two potions mix knows that it is not mere chemical recombination that they are witnessing; it has more in common with a dog fight.
There is that tantalizing link between potions and oozes, which may very well be two ends of the same spectrum.