This conference is the follow-up of two very successful meetings:

• The quantum cascade laser workshop, the last edition of which was in Bari, co-chaired by Prof. G. Scamarcio (Univ Bari) and Prof. Q. Hu (MIT)
• The school on quantum cascade lasers in Cortona (Italy), organized in the framework of a EU-Marie Curie action POISE (http://www.ldsd.group.shef.ac.uk/poise/), co-chaired by Prof. A. Tredicucci (Scuola Normale di Pisa) and Prof. J. Cockburn (Univ. Sheffield)

Because these two workshops had similar scientific content but format that complemented each other, it was decided that the next occurrence would combine both aspects.