Any good that you keep to be sold in the future is inventory. if you kept it for the use of your business, its supply. Let's say you have a pen & I have a pen. you keep the pen because you're in the pen business & you plan to sell it. i have the same pen, but i intend to use it for writing. So the pen is inventory for you but supply for me.
Any self published book of yours is inventory, safely assuming you kept it to sell. canvasses, apply the intent-to-sale rule. if you plan to sell the canvas its inventory. otherwise its supplies.
Any good that you keep to be sold in the future is inventory. if you kept it for the use of your business, its supply. Let's say you have a pen & I have a pen. you keep the pen because you're in the pen business & you plan to sell it. i have the same pen, but i intend to use it for writing. So the pen is inventory for you but supply for me.
Any self published book of yours is inventory, safely assuming you kept it to sell. canvasses, apply the intent-to-sale rule. if you plan to sell the canvas its inventory. otherwise its supplies.