I have literally looked in all the places its supposed to be in, I used advice from UESP and Elder-Scrolls wikia but its not there, and I know I never picked it up. I have completed the Dragonborn main quest and have all Black Books..if that matters.

Anyway, I really want the summon seeker spell but cant get the tome anywhere, I heard rumors that Talvas Fathryon sells the tome, but hes only selling Flame Atronach, Familiar, and Ash Guardian for me. Is there anyway I can possibily still get this spell tome without loading back or starting over?