The International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), is the oldest and largest continuous forum devoted to the science and technology of long-wavelength radiation. The scope of the conference includes all scientific and technological activities from millimeter-waves to the THz regime and on to the far-infrared region of the electromagnetic spectrum. This covers a very wide range of disciplines, encompassing everything from micro- and nano-scale devices and structures to large-scale accelerators and tokamaks and their applications. Presentations at this conference address issues ranging from basic physics, chemistry, electrical engineering and materials science to problems in high frequency circuits and systems, communications, antennas and optics, imaging and spectroscopy, and much, much more. The conference brings together scientists and technologists from more than 30 countries and typically hosts 600-700 participants. Contributed papers are archived on IEEEXplore, and IEEE is a long term technical co-sponsor of the conference series - currently celebrating 40 years since the first event was held in Atlanta, Georgia in 1974. We wish to welcome all attendees to Hong Kong for the first time in 2015, where we know you will have a great week!