Astronomy in Focus presents the most relevant contributions from the Focus Meetings included during the XXX IAU General Assembly held in Vienna, Austria, from 20-31 August 2018. Focus meetings are proposed by groups of scientists with aims to promote cross-disciplinary interactions while maintaining a well-defined focus on a particular topic. They usually address a new scientific area or an emerging field that is not well, or in some cases not at all, represented under the IAU's existing Commission structure. The XXX IAU General Assembly included six scientific symposia, a special symposium focused on the IAU's centenary and fifteen Focus Meetings. The latter comprised twelve scientific Focus Meetings plus two on the mission and activities of the IAU Offices of Astronomy Outreach and Astronomy for Development and the final one promoted by the Working Group on Global Coordination of Ground and Space Astrophysics.