Head First book author here -- I wrote Head First C#, Head First PMP, and Head First Agile (and three other, non-Head First O'Reilly books) -- and I wanted to push back on your first point. We work really, really hard to include quality content. But I understand why people sometimes make the point that you made; I did the same thing myself at first.

It's easy to dismiss one of our Head First books as less-than-serious if you're not used to the format. There are a lot of pictures. There's a LOT of whitespace. There's redundancy; we'll say the same thing more than once. And most of all, when we do our job right they're not boring -- which, to many people, reads as non-serious. But we find that when people approach Head First books with an open mind, they find that it's actually a really effective way to get a lot of information into your brain quickly and easily.

We also know that while a lot of people love the informal and highly visual format, some people just can't stand it. There are some people who just want a dense, concise, terse book that they can absorb all at once. Readers like that just won't like Head First books. That's why every Head First book starts with an introduction that says who the book is for and who it's not for. Coincidentally, my coauthor, Jenny Greene, and I just did an interview on Dave Prior's "Drunken PM" podcast, and the first question he asks us is about this "Who this book isn't for" section: https://www.projectmanagement.com/blog-post/34188/Head-First...

Short, shameful confession: I had a similar reaction to yours when I first saw Head First Design Patterns; I dismissed it out of hand, ostensibly because there were some less-common design patterns from GoF that it didn't cover, but really because I just didn't "get" the format. A year later, when our editor at O'Reilly floated the idea of writing Head First PMP, I went back to it and really read it, this time with a much more open mind (for example, I actually did all of the code exercises instead of just reading them). I realized why I'd made my earlier mistake in dismissing the book -- and gained a lot of respect for how much work Eric Freeman, Elisabeth Robson, Kathy Sierra, and Burt Bates had put into it. They were really careful about what they chose to cover, and covered those topics really thoroughly. They give you several different chances to "get" each concept, showing it to you from different angles so that you really absorb the full context. They put a lot of care into managing the pace of the book so it's a steady stream of learning and not a flood. They repeated things that needed repeating. And it all works. Really, really well.

I thought I'd understood design patterns pretty well before I really read Head First Design Patterns. afterwards, I was actually better at using them in code in real life. When I'm not writing books or training teams, I'm writing code both professionally with teams and as outside of work. The incredible quality of the content in their book helped me understand design patterns better.

Jenny and I strive to bring the same care to our Head First books. I think we've done a pretty good job of including quality content that's worth our readers' time; I hope they agree.