There is hardly any information available on the chronic effects of low doses of chemical warfare agents, but there is a growing body of data on the chronic effects of exposure to other toxic materials (PAHs, PABs and the like). One of the four main themes of the book is thus the chronic effects of extended exposure to low doses of toxic material. There is some important contemporary work on the effects of such materials on cellular material and genes. The book's second main theme is the decontamination of CW facilities, centring on two topics: bioremediation and concrete. Both before and after decontamination, one needs to be able to analyze residual toxics at trace level - possibly even at parts per trillion or parts per quadrillion levels. Techniques for use at these levels do not permit the identification of compounds. Neither LIDAR nor solid phase microextraction, used for air monitoring, offer this sort of sensitivity. Toxic waste has to be disposed of, and plasma arc technology and chemical oxidation are discussed as techniques to reduce toxicity to acceptable levels - if such can be specified. The eternal question in such matters, of course, is "How clean is clean enough?" , and the discussion of this theme outlines two approaches: a regulatory approach and one based on quantitative risk analysis.