This is a book about the insects and fungi that may appear in building timbers if unnoticed or unavoidable maintenance problems allow them to remain damp. There are two options if a problem is found. The building owner or occupier may require the organism to be rapidly exterminated and a document issued which seems to reassure that it will not come back. In this case they must accept generally expensive and frequently destructive chemical treatments using more or less noxious pesticides. Unfortunately each decade’s panacea has usually become the next decade’s poison and a pesticide accepted as ‘safe’ has proved elusive. Pesticides may be used in a ‘safe manner’ and this is the province of the remedial company, but legislation is continuously evolving and pesticides are becoming increasingly unpopular. The second option is to take a little time and to consider the problem. This may not always be possible, but in many situations a little background knowledge can make a considerable difference. Frequently an understanding of why the damage has occurred, together with an understanding of insect or fungi requirements and limitations, can reduce treatments or show that they are unnecessary.