Shammos said that those alive don't know about this skill. Then you may want to find those who aren't alive. Go to Sleepywood. Perhaps you will find your answers there.

According to Shammos, some of the trainees from Sleepywood may know about this ultimate skill. The Rememberer has been training for a long time. You can ask for help.

If you don't go, the clue of Bowman's ultimate skill will disappear and be lost to you...

Do you need to see me? The book...? Bowman's ultimate skill? I gather that's why you're here.

Sadly, I have no idea about that. But I can find somebody who knows more.