Hadley Wickham recently released an online version of Mastering Shiny. The book is great! If you haven’t read it, do it fast! On a side note, it is really amazing how much of good and curated content you can get for free in R. When I started programming back in 2007, the first step was buying a brand new – and sometimes expensive – book about the language. There were blogs and other sites, but most content was very basic and not curated, meaning that the posted code most of the time did not work.