Office 365 provides a nice set of basic and rich integration options for both Exchange and non-Exchange messaging systems. We learned about the base integration options to enable a simplified logon process for users to an extended integration option, enabling rich coexistence for on-premise and Exchange Online organizations. These options should help you work through your planning process, preparing you for the deployment of these options.
Based on the integration options for professionals, small businesses, and enterprises, you have to decide which path is correct for your organization. If you choose to leverage the professional or small business path, then the next chapter is a right fit for you, If you plan to leverage the enterprise path, you may want to skip ahead to Chapter 7, Preparing for a Hybrid Deployment and Migration.