Portable and convenient, books and manuals can nail down complex technical topics as well as teach good business prose.

When evaluating books, look for a well-organized table of contents, comprehensive index, summaries and diagrams throughout that reinforce key points and allow employees to pace themselves, to repeat sections they don't understand, and to skip things they already know. A glossary so employees can quickly refer to unfamiliar terms can be a real plus, too.

Print is affordable. A book on good management practices, for example, may cost about $25 compared to a $1,000 seminar that delivers the same content.

Although a great reference tool, print is less useful when an overly complex subject must be taught to a person with little basic understanding.