During the last decades atomic clocks and frequency standards have become an important resource for advanced economies with impact ranging from satellite navigation (GPS, GLONASS, Galileo) to high speed communication networks, where they ensure synchronisation of data packets at ever higher bit rates. In this field the wake of the new millennium has been marked by the invention of frequency comb technology, a discovery so important that it was awarded the Nobel Prize in Physics in 2005. Femtosecond comb technology enables two major advances (i) a factor of 1000 improvement in sensitivity and accuracy over current atomic clock technology and (ii) the possibility to create a precision frequency synthesizer ranging from the Hz level up to 10^17 Hz or even higher, i.e. covering the electromagnetic spectrum from DC to the soft x-ray regime. The technological impact of this current development is likely to be tremendous, opening new applications, e.g. in “relativistic geodesy”, where ultraprecise clocks sense the gravitational potential via the redshift arising from general relativity. This might open new markets in oil and mineral exploration, supervision of CO2 sequestration and hydrology and climate research.However the technologies associated with optical clocks and frequency standards are still in the laboratory stage and experts in the field are desperately needed for developing commercially viable systems and applications. This ITN is addressing this issue by implementing a training programme covering all aspects from the atomic reference and ultrastable lasers to frequency comb synthesis, precision frequency distribution and commercial system technology. It focuses on technological developments enhancing the technology readiness level of the new optical atomic clocks, enhancing the chance that they are picked up by the commercial sector. At this initial stage the vehicle will be space technology, which is promising the first high-precision applications.