Congratulations to sometime Cambridge student Emily Riehl, now at Johns Hopkins. Her very illuminating lecture notes, aimed at beginners in category theory (albeit mathematically perhaps rather sophisticated beginners) have become a book, *Category Theory in Context*, published in a new series of ‘Modern Math Originals’* *by Dover Books. This is available now in the US, and at the end of the year in the UK.

There has been a link to Emily Riehl’s evolving notes on the category theory page here for a couple of years, and the publishers have kindly allowed her to continue to host a free PDF copy of the book. So you can take a look already if you don’t know her work — but at this low price, it will be really nice to have a paper copy (and of course, tell your library).