The International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), begun in 1974, is the oldest and largest continuous forum specifically devoted to the field of ultra high frequency electronics and applications. In 2004 the original conference series - International Conference on Infrared and Millimeter Waves (IRMMW) joined up with the International Conference on THz Electronics to form the Joint 29th International Conference on Infrared and Millimeter Waves and the 12th International Conference on Terahertz Electronics (IRMMW-THz 2004). In 2008 the conference name was shortened to the 33rd International Conference on Infrared, Millimeter, and Terahertz Waves, keeping the same general acronym: IRMMW-THz 20XX. In 2009 the conference series was formally incorporated into a permanent non-profit international society registered in the state of California, USA. The International Society of Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) has the mission statement: "Promoting the worldwide collection, dissemination and exchange of scientific and technical knowledge in the areas and disciplines involving infrared, millimeter, and terahertz waves." The IRMMW-THz Society has a permanent Board of Directors, official By-Laws, and independent financial resources, and will assure the continuation of the conference series for the foreseeable future. The IRMMW conference and its long standing accompanying monthly publication, The Journal of Infrared, Millimeter and Terahertz Waves, were among the very first scientific outlets for the burgeoning field of far infrared components and instruments that arose in the mid 1970s. The scope of the conference extends from millimeter wave devices, components and systems to far-infrared detectors and instruments, and encompasses micro- and nano-scale structures to large-scale accelerators and Tokamaks and their applications. In 2011 a new focused THz journal, IEEE Transactions on Terahertz Science and Technology was added to the list of linked technical outlets for members of the IRMMW-THz Society. The international organizing committee is composed of world-recognized experts from eleven countries. The conference typically alternates between the USA, Asia and Europe on a three year cycle. Past conferences have been supported by US agencies such as IEEE, APS, DOE and DoD and dozens of local societies within the hosting countries. In 2003 both the IRMMW and THz Electronics conferences were held sequentially in Japan. Total attendees for both events was 520 registrants from 18 countries with 340 submitted papers. After 2003 the two conferences joined and attendance in 2004 (Karlsruhe, Germany) exceeded 450 scientists from 28 countries with over 400 contributed papers. The 2005 conference in Williamsburg, Virginia, hosted 300 scientists from 23 countries with more than 375 contributed papers. In Shanghai, China in 2006 more than 550 papers were submitted representing 28 countries and regions, the largest venue in recent memory. The 2007 conference in Cardiff, Wales, UK ended with more than 430 participants from 18 countries and 550 submitted papers. The 2008 conference in Pasadena had over 460 papers from 32 countries. The 2009 venue in Busan, Korea had over 535 attendees from 43 countries. In 2010 the conference in Rome hosted the largest crowd to date, with 640 participants from around the world. Sandwiched between the optical on the short wavelength side and radio on the long wavelength extreme, the Terahertz or Far-Infrared has long been considered the last remaining scientific gap in the electromagnetic spectrum. Due to the historic role the IRMMW conference has played in bridging this gap by bringing together international researchers in many diverse fields - from space science to nuclear fusion - and recently chemistry and biology, the organizing committees would again like to reach out to scientists in adjacent fields who can benefit from recent developments in the far-IR. In the last few years interest in terahertz imaging and spectroscopy from the biology, security, ultra-fast chemistry and health science communities has grown exponentially as new instrumentation and techniques have begun to make their way into many laboratories world-wide. This is especially the case in Europe and Japan, both of which have thriving cross-disciplinary programs supporting new applications in this frequency domain. As a consequence the conference organizing committees have significantly expanded the scope and the participating research communities. They have now included a special focus on terahertz techniques and applications, including both the traditional radio frequency domain, and the new fast pulse time domain approaches to generating, detecting and using high frequency energy. The conference offers the attendee a chance to hear and participate in a wide range of topic areas that span all aspects of Infrared, Terahertz and Millimeter-Wave (IR, THz, and MMW) technology and applications from quantum physics, chemistry, and biology to radio astronomy, plasma physics and security. Over the coming years we are looking forward to very well attended and internationally supported cross-disciplinary conference venues that will set IRMMW-THz up as the pre-eminent conference for information exchange in the "Terahertz Gap."