Enterprise Javabeans enable you to support distributed business applications in which the components can be located on different platforms in various locations. This provides flexibility at the expense of complexity. An EJB is called by a client and interacts with any CTM (component transaction monitor) which supports the EJB specification. EJBs live in the middle tier of the three tier model: client presentation is the first tier, business logic (encapsulated in EJBs) in the second and database back ends are the third. The author of Enterprise Javabeans, Second Edition is currently the lead architect for OpenEJB. He spends the first 80 pages describing distributed object architectures, and it"s barely enough. The English language strains to encompass complex and unfamiliar relationships using familiar words. A book on this subject can read a little like a mediaeval grimoire, for much the same reasons. Fortunately, while this theoretical background is necessary to understand how EJBs work, most of the book is follows the development of an example EJB designed to be used by a company running a passenger liner. This enables the author to produce lots of demonstration code and to discuss the difference between entity and session beans (think nouns and verbs), stubs, skeletons, containers, XML deployment descriptors, JNDI Naming Context, transaction management, security models, data persistence and so on. To benefit from Enterprise Javabeans you need basic Java skills, a good grasp of OOPs and some understanding of the data processing needs of large businesses. There is a need for a quick and dirty cookbook approach to EJB development, which this isn"t. Most programmers just want to know how, but Richard Monson-Haefel ensures you know why as well. This makes for a harder, if more interesting, read, which does repay study on several levels. --Steve Patient