The early botanists and pioneer mycologists of the nineteenth century recognised the fact that the fungi both large and small are ecologically connected to the herbaceous plants and trees among which they grow, but many mycologists since have tended to neglect these early observations. Although the importance of the fungi in the economy of the woodland, copse, field and marsh is well-known, mycologists and ecologists alike have been rather slow to appreciate that the fungi can be just as good indicators of soil conditions, if not better, than many other plants. Perhaps it is rash to attempt such a treatment as you find here because we know so little of the reasons why a particular fungus prefers one habitat to another. However, it is envisaged and hoped that, if a framework is provided, accurate field-notes can gradually be accumulated and many of the secrets yet to be uncovered explained. _Where to look_ Fungi can be found in most situations which are damp at some time of the year. Searching for fungi can begin as soon as the spring days become warm, although even in the colder periods of winter several finds can be made. In summer it gets very dry and this necessitates collecting in damper areas, such as marshes, alder-carrs, swamps and moorland bogs. After a heavy storm in summer, on the edges of paths and roadsides, woodland banks, in clearings in woods and in gardens, fungi can be collected within a few days of the rain, but collecting normally reaches a climax in August-September, the precise date depending on the locality and the individual character of the particular year. All woodlands are worth visiting, particularly well-established woods with a mixture of trees. Pure pine-woods do not seem to be as good as pine-woods with scattered birch; plantations are often disappointing except after heavy rain or late in the season, even well into November in mild years. Pure birch and beech, the latter particularly when on chalky soils, are excellent areas to visit. Oak is possibly not as good but areas with willow and alder have many unique species. The edge of woods, sides of paths or clearings are usually more productive areas to search in than is the depth of the wood, and a small plot of trees can be much more rewarding than a large expanse of woodland. After some time one is able to judge the sort of place which will yield fungi. Rotten and burnt wood are very suitable substrates for they retain the moisture necessary for growth of fungi even in dry conditions, so allowing fructification to take place.