diff --git a/chrome/content/zotero/lookup.js b/chrome/content/zotero/lookup.js
index 1f4a3cbc0..7239ecc19 100644
--- a/chrome/content/zotero/lookup.js
+++ b/chrome/content/zotero/lookup.js
@@ -31,71 +31,126 @@ const Zotero_Lookup = new function () {
 	/**
 	 * Performs a lookup by DOI, PMID, or ISBN
 	 */
-	this.accept = function() {
-		var identifierElement = document.getElementById("zotero-lookup-textbox");
-		var identifier = identifierElement.value;
-		
-		var doi = Zotero.Utilities.cleanDOI(identifier);
-		if(doi) {
-			var item = {itemType:"journalArticle", DOI:doi};
-		} else {
-			identifier = identifier.trim().replace(/[\- ]/g, "");
-			if(identifier.length == 10 || identifier.length == 13) {
-				// ISBN
-				var item = {itemType:"book", ISBN:identifier};
-			} else {
-				// PMID; right now, PMIDs are 8 digits, so there doesn't seem like we will need to
-				// discriminate for a fairly long time
-				var item = {itemType:"journalArticle", contextObject:"rft_id=info:pmid/"+identifier};
+	this.accept = function(textBox) {
+		var identifier = textBox.value;
+		//first look for DOIs
+		var ids = identifier.split(/[\s\u00A0]+/);	//whitespace + non-breaking space
+		var items = [], doi;
+		for(var i=0, n=ids.length; i<n; i++) {
+			if(doi = Zotero.Utilities.cleanDOI(ids[i])) {
+				items.push({itemType:"journalArticle", DOI:doi});
 			}
 		}
-		
-		var translate = new Zotero.Translate("search");
-		translate.setSearch(item);
-		
-		// be lenient about translators
-		var translators = translate.getTranslators();
-		translate.setTranslator(translators);
-		
-		translate.setHandler("done", function(translate, success) {
-			identifierElement.style.opacity = 1;
-			identifierElement.disabled = false;
-			document.getElementById("zotero-lookup-progress").hidden = true;
-			if(success) {
-				document.getElementById("zotero-lookup-panel").hidePopup();
-			} else {
-				var prompts = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
-				                        .getService(Components.interfaces.nsIPromptService);
-				prompts.alert(window, Zotero.getString("lookup.failure.title"),
-					Zotero.getString("lookup.failure.description"));
+
+		//then try ISBNs
+		if(!items.length) {
+			//first try replacing dashes
+			ids = identifier.replace(/[\u002D\u00AD\u2010-\u2015\u2212]+/g, "");	//hyphens and dashes
+
+			var ISBN_RE = /(?:\D|^)(\d{10}|\d{13})(?!\d)/g;
+			var isbn;
+
+			while(isbn = ISBN_RE.exec(ids)) {
+				items.push({itemType:"book", ISBN:isbn[1]});
 			}
-		});
-		
+
+			//now try spaces
+			if(!items.length) {
+				ids = ids.replace(/[ \u00A0]+/g, "");	//space + non-breaking space
+				while(isbn = ISBN_RE.exec(ids)) {
+					items.push({itemType:"book", ISBN:isbn[1]});
+				}
+			}
+		}
+
+		//finally try for PMID
+		if(!items.length) {
+			// PMID; right now, PMIDs are 8 digits, so there doesn't seem like we will need to
+			// discriminate for a fairly long time
+			var PMID_RE = /(?:\D|^)(\d{8})(?!\d)/g;
+			var pmid;
+			while(pmid = PMID_RE.exec(identifier)) {
+				items.push({itemType:"journalArticle", contextObject:"rft_id=info:pmid/"+pmid[1]});
+			}
+		}
+
+		if(!items.length) {
+			var prompts = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
+											.getService(Components.interfaces.nsIPromptService);
+			prompts.alert(window, Zotero.getString("lookup.failure.title"),
+				Zotero.getString("lookup.failureToID.description"));
+			return false;
+		}
+
+		var notDone = items.length;	 //counter for asynchronous fetching
+		var successful = 0;					//counter for successful retrievals
+
 		var libraryID = null;
 		var collection = false;
 		try {
 			libraryID = ZoteroPane_Local.getSelectedLibraryID();
 			collection = ZoteroPane_Local.getSelectedCollection();
 		} catch(e) {}
-		translate.setHandler("itemDone", function(obj, item) {
-			if(collection) collection.addItem(item.id);
-		});
-		
-		identifierElement.style.opacity = 0.5;
-		identifierElement.disabled = true;
-		document.getElementById("zotero-lookup-progress").hidden = false;
-		
-		translate.translate(libraryID);
+
+		textBox.style.opacity = 0.5;
+		textBox.disabled = true;
+		document.getElementById("zotero-lookup-progress").setAttribute("collapsed", false);
+
+		var item;
+		while(item = items.pop()) {
+			(function(item) {
+				var translate = new Zotero.Translate("search");
+				translate.setSearch(item);
+
+				// be lenient about translators
+				var translators = translate.getTranslators();
+				translate.setTranslator(translators);
+
+				translate.setHandler("done", function(translate, success) {
+					notDone--;
+					successful += success;
+
+					if(!notDone) {	//i.e. done
+						textBox.style.opacity = 1;
+						textBox.disabled = false;
+						document.getElementById("zotero-lookup-progress").setAttribute("collapsed", true);
+						if(successful) {
+							document.getElementById("zotero-lookup-panel").hidePopup();
+						} else {
+							var prompts = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
+																			.getService(Components.interfaces.nsIPromptService);
+							prompts.alert(window, Zotero.getString("lookup.failure.title"),
+								Zotero.getString("lookup.failure.description"));
+						}
+					}
+				});
+
+				translate.setHandler("itemDone", function(obj, item) {
+					if(collection) collection.addItem(item.id);
+				});
+				
+				translate.translate(libraryID);
+			})(item);
+		}
+
 		return false;
 	}
 	
 	/**
 	 * Handles a key press
 	 */
-	this.onKeyPress = function(event) {
+	this.onKeyPress = function(event, textBox) {
 		var keyCode = event.keyCode;
+		//use enter to start search, shift+enter to insert a new line. Flipped in multiline mode
+		var multiline = textBox.getAttribute('multiline');
+		var search = multiline ? event.shiftKey : !event.shiftKey;
 		if(keyCode === 13 || keyCode === 14) {
-			Zotero_Lookup.accept();
+			if(search) {
+				Zotero_Lookup.accept(textBox);
+			} else if(!multiline) {	//switch to multiline
+				var mlTextbox = Zotero_Lookup.switchToMultiline(textBox);
+				mlTextbox.value = mlTextbox.value + '\n';
+			}
 		} else if(keyCode == event.DOM_VK_ESCAPE) {
 			document.getElementById("zotero-lookup-panel").hidePopup();
 		}
@@ -118,9 +173,43 @@ const Zotero_Lookup = new function () {
 	/**
 	 * Cancels the popup and resets fields
 	 */
-	this.onHidden = function(event) {
-		if (event.target.id == 'zotero-lookup-panel') {
-			document.getElementById("zotero-lookup-textbox").value = "";
+	this.onHidden = function() {
+		var txtBox = document.getElementById("zotero-lookup-textbox");
+		var mlTextbox = document.getElementById("zotero-lookup-textbox-multiline");
+		txtBox.value = "";
+		mlTextbox.value = "";
+		//switch back to single line textbox
+		mlTextbox.setAttribute("collapsed", true);
+		document.getElementById("zotero-lookup-buttons").setAttribute("collapsed", true);
+		txtBox.setAttribute("collapsed", false);
+		txtBox.focus();
+	}
+
+	/**
+	 * Converts the textbox to multiline if newlines are detected
+	 */
+	this.adjustTextbox = function(txtBox) {
+		if(txtBox.value.trim().match(/[\r\n]/)) {
+			Zotero_Lookup.switchToMultiline(txtBox);
+		} else {
+			//since we ignore trailing and leading newlines, we should also trim them for display
+			//can't use trim, because then we cannot add leading/trailing spaces to the single line textbox
+			txtBox.value = txtBox.value.replace(/^([ \t]*[\r\n]+[ \t]*)+|([ \t]*[\r\n]+[ \t]*)+$/g,"");
 		}
 	}
+
+	/**
+	 * Performs the switch to multiline textbox and returns that textbox
+	 */
+	this.switchToMultiline = function(txtBox) {
+		//copy over the value
+		var mlTextbox = document.getElementById("zotero-lookup-textbox-multiline");
+		mlTextbox.value = txtBox.value;
+		//switch textboxes
+		txtBox.setAttribute("collapsed", true);
+		mlTextbox.setAttribute("collapsed", false);
+		mlTextbox.focus();
+		document.getElementById("zotero-lookup-buttons").setAttribute("collapsed", false);
+		return mlTextbox;
+	}
 }
diff --git a/chrome/content/zotero/zoteroPane.xul b/chrome/content/zotero/zoteroPane.xul
index 84a7ba4dd..978e34539 100644
--- a/chrome/content/zotero/zoteroPane.xul
+++ b/chrome/content/zotero/zoteroPane.xul
@@ -1,4 +1,4 @@
-<?xml version="1.0"?>
+<?xml version="1.0"?>
 <!--
     ***** BEGIN LICENSE BLOCK *****
     
@@ -39,7 +39,7 @@
 	
 	<script src="include.js"/>
 	<script src="zoteroPane.js" type="application/javascript;version=1.8"/>
-    <script src="fileInterface.js"/>
+	<script src="fileInterface.js"/>
 	<script src="reportInterface.js"/>
 	<script src="timelineInterface.js"/>
 	<script src="recognizePDF.js"/>
@@ -146,9 +146,15 @@
 							<vbox>
 								<description>&zotero.lookup.description;</description>
 								<stack>
-									<progressmeter id="zotero-lookup-progress" mode="undetermined" hidden="true"/>
-									<textbox id="zotero-lookup-textbox" onkeypress="return Zotero_Lookup.onKeyPress(event)" flex="1"/>
+									<progressmeter id="zotero-lookup-progress" mode="undetermined" collapsed="true"/>
+									<vbox>
+										<textbox id="zotero-lookup-textbox" onkeypress="return Zotero_Lookup.onKeyPress(event, this)" oninput="Zotero_Lookup.adjustTextbox(this)" flex="1" newlines="pasteintact"/>
+										<textbox id="zotero-lookup-textbox-multiline" onkeypress="return Zotero_Lookup.onKeyPress(event, this)" multiline="true" rows="5" wrap="off" collapsed="true" flex="1"/>
+									</vbox>
 								</stack>
+								<hbox align="start" id="zotero-lookup-buttons" class="zotero-button-clear-image" collapsed="true">
+									<button label="&zotero.lookup.button.search;" align="start" oncommand="Zotero_Lookup.accept(document.getElementById('zotero-lookup-textbox-multiline'))"/>
+								</hbox>
 							</vbox>
 						</panel>
 					</toolbarbutton>
diff --git a/chrome/locale/en-US/zotero/zotero.dtd b/chrome/locale/en-US/zotero/zotero.dtd
index c3bbb9123..e4e0a9b04 100644
--- a/chrome/locale/en-US/zotero/zotero.dtd
+++ b/chrome/locale/en-US/zotero/zotero.dtd
@@ -92,7 +92,7 @@
 <!ENTITY zotero.toolbar.newItem.label					"New Item">
 <!ENTITY zotero.toolbar.moreItemTypes.label			"More">
 <!ENTITY zotero.toolbar.newItemFromPage.label			"Create Web Page Item from Current Page">
-<!ENTITY zotero.toolbar.lookup.label				"Add Item by Identifier">
+<!ENTITY zotero.toolbar.lookup.label				"Add Item(s) by Identifier">
 <!ENTITY zotero.toolbar.removeItem.label				"Remove Item…">
 <!ENTITY zotero.toolbar.newCollection.label			"New Collection…">
 <!ENTITY zotero.toolbar.newGroup						"New Group…">
@@ -139,7 +139,8 @@
 <!ENTITY zotero.tagSelector.renameTag				"Rename Tag…">
 <!ENTITY zotero.tagSelector.deleteTag				"Delete Tag…">
 
-<!ENTITY zotero.lookup.description				"Enter the ISBN, DOI, or PMID to look up in the box below.">
+<!ENTITY zotero.lookup.description				"Enter one or more ISBNs, DOIs, or PMIDs to look up in the box below.">
+<!ENTITY zotero.lookup.button.search				"Search">
 
 <!ENTITY zotero.selectitems.title						"Select Items">
 <!ENTITY zotero.selectitems.intro.label				"Select which items you'd like to add to your library">
diff --git a/chrome/locale/en-US/zotero/zotero.properties b/chrome/locale/en-US/zotero/zotero.properties
index 472d7d8ab..3a0f1b24e 100644
--- a/chrome/locale/en-US/zotero/zotero.properties
+++ b/chrome/locale/en-US/zotero/zotero.properties
@@ -756,6 +756,7 @@ rtfScan.scannedFileSuffix			= (Scanned)
 
 lookup.failure.title				= Lookup Failed
 lookup.failure.description			= Zotero could not find a record for the specified identifier. Please verify the identifier and try again.
+lookup.failureToID.description		= Zotero could not find any identifiers in your input. Please verify your input and try again.
 
 locate.online.label					= View Online
 locate.online.tooltip				= Go to this item online
diff --git a/chrome/skin/default/zotero/overlay.css b/chrome/skin/default/zotero/overlay.css
index 47bb89181..cefd45b85 100644
--- a/chrome/skin/default/zotero/overlay.css
+++ b/chrome/skin/default/zotero/overlay.css
@@ -266,6 +266,10 @@
   display: none;
 }
 
+.zotero-button-clear-image {
+  list-style-image: none
+}
+
 #zotero-tb-collection-add
 {
 	list-style-image: url('chrome://zotero/skin/toolbar-collection-add.png');