I've been planning something along these lines for PHP, but PHP in and of itself has plenty of learning resources. That's not to say they're any good, per se.

I've been planning something along these lines for PHP, but PHP in and of itself has plenty of learning resources. That's not to say they're any good, per se. The focus thus shifts on to correcting the many mistakes these other learning resources make. That might be poor security (SQL injection, XSS, etc.), use of deprecated functions (mysql_* functions), and maintaining your website as an unholy tangle of intermingled HTML, CSS, JS and PHP. This is what I'm more interested in doing. I don't personally see much value in writing about much else (like, idiomatic PHP), because the language itself lacks an opinion on what good code and bad code is, or whether it should be procedural or OOP (see DateTime and mysqli for examples where there is an interface for both styles). Trying to establish a 'norm' for these things would be nothing less than Sisyphean in nature. Compare this to Python and Ruby, where these books flourish because the language itself makes it easier to write about.