I am following your server side with vapor screencasts since the beginning and I am impressed about the simplicity and implenting in parallel my own REST API using vapor.
Every backend guy can follow easily every cast and add more features to its app.
For me book would be great but more covering the REST API part to really show how vapor and swift can compete with other backend as Java, PHP, nodeJS.
I am not a fan of ‘another UI technology’ because the community is so big on Angular and React.
I would by far split it and show more REST API tricks and middleware features, other vapor based frameworks in the book.
Thanks @rwenderlich for world class screencasts.