Runequest 1ts edition WIS Attribute


I have just started a new Runequest campaign using Mongooses 1st edition, and I am making a worksheet showing all skills, spells and such. My question to Ya'all is this. In Legendary Heroes they have new skills but they use the WIS attribute. When and what book is that attribute created? I have read all of the books that I have and have not found any mention of WIS except in Legendary Heroes. Thank you in advance for any help you give.