The notebooks are intended, in the first instance, for my own use, a way of storing ideas, references, questions, puzzles, connections, possible connections, mistakes (unavoidably), things to look at or look into. My interests change; my time is limited; I know very little and have less to say about many things. For this reason, many of the notebooks are little more than placeholders. These do grow over time into more substantial documents, some of them anyway; in the meanwhile, it's not my fault if the search-engines serve them up to you.