Richard Zach, one of the subject editors, has noted on his blog that there’s a new entry on the Stanford Encyclopedia by Herb Enderton on Second-order and Higher-order Logic. The SEP is really developing quite terrifically, and it seems to me that the average standard of the entries on this freely accessible resource is distinctly better than e.g. on the expensive Routledge Encyclopedia. (I did write one entry for the latter, on C.D. Broad, still one of my favourite early 20th century philosophers: but I was given just half the space of his entry in the old Edwards encyclopedia — and that seems to be indicative of the shortcomings of the Routledge Encyclopedia: it covers too much too thinly.)