The Open air museum “Old Village” proudly presents the fourth number of International Yearbook “Open air museums” for 2015 thus continuing successful international cooperation with institutions across the globe. The topic to which ten authors contributed was provocative and challenging domain of museology and museum practice. Throughout papers in “Unheard Voices” the authors put the new lights on several domains: open air museums outside European context, representations, interpretations dealing with or involving marginalized groups and ideas and practices and concepts in the field of heritage that could give new insight and offer new perspectives and ideas. In the Yearbook 2015 there are independent or joint representatives of Australia/China, Canada, Denmark, Germany, Japan, Japan/Georgia, Norway, Serbia, United Kingdom and United States.