This book is addressed to those who love mushrooms, who love the whole rich world of mushrooms in the same way that many love the flowers of the field and the birds of the air. Mushrooms are a very important crop and are grown commercially in many countries. China grows more types of mushrooms than any other country and is the largest overall producer accounting for some 32 per cent . Worldwide, the button mushroom or white mushroom is probably the most widely grown. It is eaten both fresh and processed, especially canned. Modern production methods are highly mechanized, requiring detailed knowledge and a high level of management skill for successful and continuous cropping. Inevitably investment and production costs are high and returns have not kept pace with inflation, though the crop is still one of the most valuable in many of the countries where it is grown.