Interoperability is getting due attention after most hospitals and providers achieved significant progress in meaningfully using EHR by coordinate care within and between care settings. The next step is to electronically communicate with providers delivering care for transient and local population at sub-acute, long-term care, home care, medical home and hospice environments across the continuum of care. This lecture covers the definitions, factors leading to selecting this topic, approaches used, desired vs. actual state outcomes and gaps, and formal structures (i.e. HIEs). It then expands to implementation steps, challenges from vendors, providers and patients and ways to overcome barriers, critical success factors, conclusions and outcomes, and recommendations to get the benefits of interoperability with an example. With good planning and execution, interoperability helps achieve even more benefits of implementing EHRs by linking disparate entities and quantifying the impact in terms of HIMSS IT value STEPS metric guidelines.