As foreshadowed in Chapter I, our search for possible correspondences between Buddhist symbolism and meditation begins with an examination of the various meditative techniques and associated mental states to which the symbols might refer. This undertaking presents some daunting practical problems, of which the most obvious is its sheer magnitude. In the Visuddhi-magga, written by the Theravāda monk Buddhaghosa in the fifth century A.D., no fewer than forty ‘subjects of meditation’ are listed; 1 and if to these are added the more recent Theravāda practices and the various techniques employed in Tibetan Buddhism and Zen, the number to be considered seems impossibly large. Most Buddhists assume that even a monk practising continuously under optimum conditions may take years to master the technique of his choice. It would seem, then, that no one could hope, in a reasonable space of time, to practise the entire range of meditative techniques, let alone become sufficiently proficient in them to be qualified to appraise their relative merits.