The Merck Manual of Medical Information gives a good overview of medical science, with well-organized, accessible articles and high-quality illustrations. The program interface is launched within a standard Internet browser, bridging the transition between accessing the CD-ROM by itself and picking up its Web updates and online resources. It has all of the features users expect--sound files that say difficult-to-pronounce terms aloud, hot-linked cross-referencing, photographs and charts that illustrate the text--and allows smoother navigation than earlier programs of this type. Generally easy to use, the interface does have a tendency to open a new browser window for every minor function, which forces users to flip back and forth between sections of data. Additionally, the cross-referencing links and search engine are designed in a frustratingly opaque fashion, making the search for specific data a hit-and-miss experience in the beginning.