A lectern is a key tool when creating spells. When the ingredients of any given spell are needed to be placed on the crafting altar, they hover above the lectern, as an indicator. Besides creating spells the lectern is an organizer, as it can showcase books (Such as the Arcane Compendium) organized so that one can read them directly, without having the book in their inventory.
The lectern should be placed in front of one of the four pillars when building a Crafting Altar. When making a spell, the spell's book must first be placed on the lectern (Note: the spell recipe MUST be signed and closed before it can be placed on the lectern). Then, when the ingredients of the spell are needed to be thrown on the crafting altar, they appear hovering directly above it.
The lectern can display books, similar to the appearance of a Minecraft Enchanting table. Players can right click upon the lectern to read the contents of the book that is currently on it. A book can be removed from the lectern by Sneak+Right clicking the book with nothing in the selected hotbar slot (ie. no item selected, using your hand).
If the book turns RED this means that the crafting altar will explode so do NOT make a spell if the book is red.
Occasionally your spell recipe simply will not go into the lectern. This is an issue that can only be solved by restarting the game on singleplayer or restarting the server on multiplayer.