Can I have another Hero's Handbook after turned one in?

I really want to get my norn armor but it's a pain to farm, so I'm trying to do the quests again.

sure - go for it.

What you want to do is get a new handbook, put it in storage, get another, put that in storage, and so on. Get like 5 HM books. Then keep one in your inventory and do a mission. Then change it with a book in storage and redo the mission. Do that mission for all all your books - then go to the next mission. This saves you a lot of time jumping from one mission to the next and changing builds between missions.

You can absolutely do more books. Bear in mind you can only get/turn in a Normal Mode book from a certain loremaster up to rank 8 in that reputation line. I realize this is likely a non-issue for you, since you only need Rank 5 for your armor, but it's still worth noting. For example, if you have Rank 8 Asuran ("Not Too Lazy"), Lexx will no longer give or receive a NM book, but you could get a new one from a Norn, Ebon Vanguard, or Deldrimor guy if you're below Rank 8 in any of them.

Hard Mode books are probably more efficient, though, if you can handle the increased difficulty. You could always speedbook it, by only doing "Against the Charr," "Curse of the Nornbear," and "A Time for Heroes" before turning the book in.

Remember that if you carry multiple Hero's Handbooks in your inventory, the page will only be filled in on the one that's firstmost in your pack -- left-to-right, top-to-bottom. If the first book already has a page filled in, and you do that mission again, you will NOT get credit. Be careful. Doing it Tharg's way, where you keep your multiples in your Xunlai, is probably safest.

And here is a link to the "title maxing with a handbook" page in the wiki which shows how many you need to fill to max a title. http://wiki.guildwars.com/wiki/Hero&...ith_a_Handbook

All I need is the norn armor, don't even want to try reach rank 10.