Milton Sheaf seems to have been broken by the valentine’s day event. Won’t sell any books, only engages in the Valentine’s stuff.
I wanted to finally buy the new poison manuals for my rogue but can’t. I tried using the valentine’s perfume & love token to see if they’d change anything but nothing changed(except my broken heart.)
Can’t you buy all that from the runes vendor?
Is the same for me i´m trying to buy the poisons manuals and he wont sell anything to me, i was wondering if it was related to the valentines event and that might be it. is really annoying and the blizz ticket system wont do anything helpful about it.
I hope they fix this soon.
You can get all of the runes out of Brokers but not the manuals for skills - that is only available via that guy.
and he wont offer anything since valentines event it seems.
Yepp he is not offering the quest therefore can’t sell the manuals and it looks like its due to the valentines day event.
Reporting the same issue here for me as well. Can’t buy any of the poison manuals 
Not sure if it would work, but have you tried accepting any/all quests from him, then checking him again? I had same problem before and that solved it.