The last book covering a part of this subject has come four years ago (Vymazal, J., and Kropfelova, L., 2008. Wastewater Treatment in Constructed Wetlands; Springer, New Yark) and the one prior to that six years ago (Crites R. W., Middlebrooks, E. O., and Reed, S. C., 2006, Natural Wastewater Treatment Systems; CRC Press, Boca Raton). Both are excellent treatises but neither covers systems based on `nutrient film technique' even as it is in this segment that most spectacular advances are currently occurring. Moreover, the state-of-the-art in all systems has advanced significantly since these books came out. The proposed book would, therefore, be much more comprehensive as well as up-to-date.