1. The document discusses the differences between a web server and application server, with application servers containing both a web container and EJB container while web servers only contain a web container and do not support clustering. 2. It describes the key components of EJB - the home interface, remote interface, and bean class - and their purposes. The home interface acts as a factory, the remote interface contains business methods, and the bean class implements both interfaces. 3. It outlines the basic architecture and workflow of how a client accesses EJBs, first looking up the home interface and then using it to get a reference to the remote interface to invoke business methods on the bean.