Well it's hopefully easy to tell why there should be a crafting guide in minecraft that could be crafted with a book and a crafting table above it! This would help those who are new to minecraft or those who can't remember how to craft,say, a cauldron. They would look it up in the guide and then they would know. And also the potions could be addded using a brewing stand when crafting the guide or after guide is crafted put the guide into the crafting table and put the brewing stand on top. it would then tell you what potions would do and how to make them. If someone (like me) didn't know how to craft a night vision potion they could go to the potion section and find out.

This idea would save lots of playing time google-ing for the minecraft wiki and searching night vision potion and then scrolling for the recipe only to forget it again 2 days later! (well i probably would knowing myself....) I hope you like this idea!
Thanks for reading!