Today we find the term "experimentation" in many documents, particularly those revolving around the topic of multi-domain operations (MDO).  But what do we mean by experimentation?  Do we all mean the same thing?  Discovery experimentation and experimentation campaigns can be very powerful in exploring and defining new capabilities whether materiel or evolution of tactics, techniques and procedures to account for new challenges. Discovery experimentation is a process for using simulation to place emerging technologies in the hands of warfighters engaged in virtual battlefields to explore the military utility of new concepts for using emerging systems. Discovery experimentation is designed to allow learning and modification from trial to trial and in that way differs significantly for both traditional scientific experimentation and technology demonstrations. It can be used to explore military utility of new technologies, development of new tactics, techniques and procedures for emerging systems, definition of requirements for control devices for new systems, and consequent needs for new training.  This tutorial will walk through the definition of discovery experimentation and experimentation campaigns, illustrating the concepts with a partial discovery campaign completed in 2016 to test a new concept in close air support.  Using the definitions and example provided, the tutorial will go on to explore the potential roles of discovery experimentation and experimentation campaigns in the evolution of concepts and capabilities for multi-domain operations.  The presentation will highlight briefly the current experiments including Army's Project Convergence, Navy's Project Overmatch, the Air Force's Digital Advanced Battle Management System of Systems (Digital ABMS), and finally the concept of Joint All Domain Command and Control (JADC2). The presentation will note the roles of constructive and LVC modeling and simulation capabilities in addition to modified live testing, including the issues of data collection.  The importance of scoping and choosing rapid modification of simulation tools will be highlighted as a means of making experimentation campaigns viable in a resource-constrained environment.