The tooltip for a crafting manual tells you what you'll learn, but only by telling you its name. It does not describe the item being crafted. If you're trying to play the game without looking at the Internet all the time, there's quite a problem. You might find a crafting manual for, e.g. "Whiteburn" but have no idea what that is.
(You also can't even tell what *kind* of crafting is required to make "Whiteburn", but I posted earlier about that problem.)
Perhaps this is intentional, and you're supposed to have to consume manuals to figure out what they make?
But then, it applies to manuals at vendors too, so you're asking characters to blindly buy mystery crafting manuals and consume them to see if they're useful!
I suggest the tooltip for the manual incorporate at least some of the description of what is being made.
At the moment the tooltip always reads "Read this manual to learn how to craft the XXX item" where XXX is what you already know from the name of the manual. Wasted space!