Index: ps/trunk/binaries/data/mods/public/gui/session/session.js
===================================================================
--- ps/trunk/binaries/data/mods/public/gui/session/session.js
+++ ps/trunk/binaries/data/mods/public/gui/session/session.js
@@ -12,8 +12,13 @@
 /**
  * Colors to flash when pop limit reached.
  */
-const g_DefaultPopulationColor = "white";
-const g_PopulationAlertColor = "orange";
+var g_DefaultPopulationColor = "white";
+var g_PopulationAlertColor = "orange";
+
+/**
+ * Seen in the tooltip of the top panel.
+ */
+var g_ResourceTitleFont = "sans-bold-16";
 
 /**
  * A random file will be played. TODO: more variety
@@ -1126,10 +1131,23 @@
 	let resNames = g_ResourceData.GetNames();
 	for (let r = 0; r < resCodes.length; ++r)
 	{
-		if (!Engine.GetGUIObjectByName("resource["+r+"]"))
+		let resourceObj = Engine.GetGUIObjectByName("resource[" + r + "]");
+		if (!resourceObj)
 			break;
+
 		let res = resCodes[r];
-		Engine.GetGUIObjectByName("resource["+r+"]").tooltip = getLocalizedResourceName(resNames[res], "firstWord") + getAllyStatTooltip(res);
+
+		let tooltip = '[font="' + g_ResourceTitleFont + '"]' +
+			getLocalizedResourceName(resNames[res], "firstWord") + '[/font]';
+
+		let descr = g_ResourceData.GetResource(res).description;
+		if (descr)
+			tooltip += "\n" + translate(descr);
+
+		tooltip += getAllyStatTooltip(res);
+
+		resourceObj.tooltip = tooltip;
+
 		Engine.GetGUIObjectByName("resource["+r+"]_count").caption = Math.floor(playerState.resourceCounts[res]);
 	}
 
Index: ps/trunk/binaries/data/mods/public/l10n/messages.json
===================================================================
--- ps/trunk/binaries/data/mods/public/l10n/messages.json
+++ ps/trunk/binaries/data/mods/public/l10n/messages.json
@@ -321,6 +321,17 @@
                 ],
                 "options": {
                     "keywords": [
+                        "description"
+                    ]
+                }
+            },
+            {
+                "extractor": "json",
+                "filemasks": [
+                    "simulation/data/resources/**.json"
+                ],
+                "options": {
+                    "keywords": [
                         "name",
                         "subtypes"
                     ],
Index: ps/trunk/binaries/data/mods/public/simulation/data/resources/food.json
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/data/resources/food.json
+++ ps/trunk/binaries/data/mods/public/simulation/data/resources/food.json
@@ -1,6 +1,7 @@
 {
 	"code": "food",
 	"name": "Food",
+	"description": "Harvest from animals, berry bushes, fish, or fields.",
 	"order": 1,
 	"subtypes": {
 		"fish": "Fish",
Index: ps/trunk/binaries/data/mods/public/simulation/data/resources/metal.json
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/data/resources/metal.json
+++ ps/trunk/binaries/data/mods/public/simulation/data/resources/metal.json
@@ -1,6 +1,7 @@
 {
 	"code": "metal",
 	"name": "Metal",
+	"description": "Mine from metal mines and quarries.",
 	"order": 4,
 	"subtypes": {
 		"ore": "Ore"
Index: ps/trunk/binaries/data/mods/public/simulation/data/resources/stone.json
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/data/resources/stone.json
+++ ps/trunk/binaries/data/mods/public/simulation/data/resources/stone.json
@@ -1,6 +1,7 @@
 {
 	"code": "stone",
 	"name": "Stone",
+	"description": "Mine from rocks, stone quarries or ruins.",
 	"order": 3,
 	"subtypes": {
 		"rock": "Rock",
Index: ps/trunk/binaries/data/mods/public/simulation/data/resources/wood.json
===================================================================
--- ps/trunk/binaries/data/mods/public/simulation/data/resources/wood.json
+++ ps/trunk/binaries/data/mods/public/simulation/data/resources/wood.json
@@ -1,6 +1,7 @@
 {
 	"code": "wood",
 	"name": "Wood",
+	"description": "Lumber from trees or groves.",
 	"order": 2,
 	"subtypes": {
 		"tree": "Tree",