Pictured on the right is history professor, Doug Howard. Professor Howard looks like he might be protecting himself from falling books. Well, reference books are stacked many shelves high, and they are heavier than most other books. They're heavy because they contain a lot of information, which often includes multiple indexes, long tables of contents, illustrations (maps, graphs, charts), statistics, long articles with bibliographies,...we could go on. ;-)

Dangerous, also, because they try to present many sides of important global and local issues so that you'll be well-informed. You may think one way on an issue of the day and then encounter a reference book on the topic and find out your view is one of many. Reference books provide a great way to become familiar with a topic at a general level. 

So, when you have a leisure moment, come to the 2nd floor and follow Professor Howard's example. Oh...and you may want to wear a helmet.