From the contents: D.J. Hamilton, M.G.D. Nix, S.G. Baran, G. Hancock, A.J. Orr-Ewing: Optical feedback cavity-enhanced absorption spectroscopy (OF-CEAS) in a ring cavity.- T. Tsai, G.Wysocki: External-cavity quantum cascade lasers with fast wavelength scanning.- B. Hinkov, F. Fuchs,Q.K.Yang, J.M. Kaster, W. Bronner, R. Aidam, K. Köhler, J.Wagner: Time-resolved spectral characteristics of external-cavity quantum cascade lasers and their application to stand-off detection of explosive.- M. Rahim, A. Khiar, F. Felder,M. Fill, H. Zogg, M.W. Sigrist: 5-μm vertical external-cavity surface-emitting laser (VECSEL) for spectroscopic applications.- B. Grouiez, V. Zeninari, L. Joly, B. Parvitte: Pulsed quantum-cascade-laser spectroscopy with intermediate-size pulses: application to NH3 in the 10 μm region.- L. Nähle, P. Fuchs, M. Fischer, J. Koeth, A. Bauer, M. Dallner, F. Langer, S. Höfling, A. Forchel: Mid infrared interband cascade lasers for sensing applications.- M. Guinet, A.W.Mantz, D.Mondelain: Performance of a 12.49 meter folded path copper Herriott cell designed for temperatures between 296 and 20 K.- A.V. Gorelik, A.L. Ulasevich, F.N. Nikonovich, M.P. Zakharich, V.A. Firago, N.S. Kazak,V.S. Starovoitov: Miniaturized resonant photoacoustic cell of inclined geometry for trace-gas detection.- J. Hodgkinson,D.Masiyano, R.P. Tatam: Gas cells for tunable diode laser absorption spectroscopy employing optical diffusers. Part 1: single and dual pass cells.- D. Masiyano, J.Hodgkinson, R.P. Tatam: Gas cells for tunable diode laser absorption spectroscopy employing optical diffusers. Part 2: Integrating spheres.- D. Hofstetter, F.R.Giorgetta, E. Baumann, Q. Yang, C.Manz, K. Köhler: Mid-infrared quantum cascade detectors for applications in spectroscopy and pyrometry.- S. Schilt,K. Zogal, B.Kögel, P.Meissner, M. Maute, R. Protasio,M.-C. Amann: Spectral and modulation properties of a largely tunable MEMS-VCSEL in view of gas phase spectroscopy applications.- J. Chen, A. Hangauer, R. Strzoda, M.-C. Amann: Tunable diode laser spectroscopy with optimum wavelength scanning.

Special issue of the 7th International Conference on Tunable Diode Laser Spectroscopy, held July 13-17, 2009 in Zermatt, Switzerland.The purpose of these meetings was to report and discuss the progress that has been made in the technical development of diode lasers and their applications in areas of fundamental research as well as real world applications of the technology. This was accomplished in a format encouraging strong interaction between researchers, device developers and semiconductor laser manufacturers. The relevant technologies include the original lead salt lasers, near-infrared diode lasers and the latest developments in mid-infrared quantum and interband cascade lasers, as well as nonlinear optical schemes.