These Transactions provide a record of the organisational and administrative activities of the IAU XXIX General Assembly which took place in Honolulu, Hawai'i, USA, in August 2015. They report and record all of the essential decisions taken by the governing body of the IAU. These include the approval of the financial accounts and of the proposed budget for the next three years, the admission of new national and individual members, the evaluation of Division and Commission reports, and the approval of Resolutions. This General Assembly also completed the internal restructuring that began in 2012, with the approval of thirty-five new Commissions, together with their elected Presidents and Organising Committees. A further change to the scientific programme of the XXIX General Assembly was the substitution of the Joint Discussions meetings and Special Sessions with a single entity, designated as Focus Meetings and published in the new 'Astronomy in Focus' series.

At the XXIX IAU General Assembly held in Honolulu from 3-14 August 2015, the meetings known as Special Sessions and Joint Discussions were replaced by new 'Focus Meetings'. Astronomy in Focus XXIXA presents the most relevant contributions from the Focus Meetings together with summaries of all the accepted papers and posters. It covers the meetings on the following areas: dynamical problems in extrasolar planet science; astronomical heritage; scholarly publishing in astronomy; statistics and exoplanets; the exploration of small worlds; ground and space astrophysics and heliophysics; laboratory astrophysics; brightness variations of the Sun and Sun-like stars; astronomy for development; and mitigating the threats of light pollution and radio frequency interference. The publications Astronomy in Focus XXIXA (together with its companion, XXIXB), the proceedings of the six main Scientific Symposia and Reports on Astronomy: Commission Legacy Reports, fully cover the XXIX IAU General Assembly.

At the XXIX IAU General Assembly held in Honolulu from 3-14 August 2015, the meetings known as Special Sessions and Joint Discussions were replaced by new 'Focus Meetings'. Astronomy in Focus XXIXB presents the most relevant contributions from the Focus Meetings together with summaries of all the accepted papers and posters. It covers the following topics: the legacy of Planck; x-ray surveys of the hot and energetic cosmos; stellar physics in galaxies; stellar explosions; gravitational waves and structure formation; the search for water and life's building blocks; red supergiants in the local Universe; advances in stellar physics from asteroseismology; scale-free processes in the Universe; and the frontiers of our understanding of cluster and galaxy evolution. The publications Astronomy in Focus XXIXB (together with its companion, XXIXA), the proceedings of the six main Scientific Symposia and Reports on Astronomy: Commission Legacy Reports, fully cover the XXIX IAU General Assembly.