Beginner Cookbook is a passive skill that unlocks some cooking recipes. All recipes unlocked by this skill are created at the Cooking Pot. Contrary to the tool-tip, only 4/9/14 (total) recipes are unlocked, meaning with three points into this skill the player will learn fourteen total recipes.
This is a multiplayer global skill, only one player needs the skill to unlock the recipes for everyone, as any unlocked global skills will be applied to all players in that world.
There are many skills that when combined together will produce a greater effect than the singular skill alone. This could be to maximize profits, improve various abilities, or quality of life increases.
Adventurer's Cookbook - Unlock 5/10/15 unique cooking recipes only obtainable from this skill point. These recipes all use ingredients obtained from foraging.
Advanced Cookbook - Unlock an additional 5/10/15 unique cooking recipes. These unique recipes are only obtainable from this skill.