Full disclosure that I did receive a copy of this book free of charge in order to provide a review. To help the review reader get some perspective on where I am coming to this book from, I have been in frontend development for some time, and have read through many guides, resources, and a lot of documentation for work and side projects, so while there is much I know, there are also some areas where I certainly could improve. That being said, I tried to look at this book with a few specific questions in mind and I tried to take into account others' perspectives by focusing on the following questions as I read through:1) How well does this book cover important CSS topics?2) How well are the topics explained to someone who is new?3) How would this work for someone who knows CSS, but wants a good reference for new material as devices and standards evolve?1) I chose to focus on a few sections where I feel especially knowledgeable as well as a few where I felt less so to try to answer this. One important thing to note is that Rich has done a great job of using a realistic, project-based approach to pulling CSS concepts together. If you follow through his book, you build a site alongside Rich that has many, if not all, of the major CSS properties of most projects you'll encounter in modern web development. Topics such as building for retina displays on modern devices, flexbox, CSS3 transitions and animations is crucial to today's UIs and Rich ensures he covers all of these and much more. At each stage he provides an explanation of why we're doing what we're doing, and what the impact is on the user. Consistently, he brings into play performance considerations and accessibility -- also two very important themes in web development today that one can no longer afford to overlook. I am genuinely impressed by how the breadth and depth here.2) I think one of my favorite things about Rich's writing is how accessible and friendly it is to the user. Reading/coding along you hear the author's voice and feel as though you're sitting and having Rich walk you through a process, not like you're reading some opaque documentation. I think this is great for anyone just dipping their toes into CSS, because it can be very intimidating and because technology evolves so quickly in this sphere, it can be hard to know what works in modern development. Rich does a great job of making the journey comfortable and addressing the concerns that a beginner might have, and might not know s/he should have (i.e. accessibility, responsiveness, browser considerations), without piling too much onto the user. The author is trying to teach you and preempt your questions with clear and concise explanations, not just list off standards or try to get you to memorize things. Rich works hard to make the reader connect concepts and I think he does an excellent job.3) This is probably the piece of the review that I can address most easily because it applies directly to me as a frontend dev who considers himself pretty knowledgeable and capable. I loved that I could read any section of Mastering CSS and pick up one or two new things -- sometimes small, sometimes not, but always interesting and helpful. I spend a lot of time on frontend development and I have read many articles, books, etc. -- it was really refreshing to get the depth that Rich provides, and to be able to get it delivered so concisely. His explanation of how retina displays work and how to ensure a great user experience with images that support their strengths was very clear and one of those "oh wow, that's awesome" moments for me. Those are the moments that I think most devs love to come across and there were many instances where Rich provided additional detailed knowledge that gave me those moments. Of course, I'll continue to use many different sources of documentation (some of which Rich provides in his notes on resources for the user), but this is definitely added to my repertoire.Overall I think Rich does exactly what he sets out to do here, and I think he does it well. Again, I did receive a free copy in order to write this review, but consider this my recommendation when comparing Mastering CSS to several other books and authors I've read on the topic. If you absorbed everything Rich wrote in this book, you would be able to tackle the vast majority of CSS & CSS3 concerns that frontend developers encounter.

This book is suitable for beginners diving into web design. The good thing about this book is that it does not assume any prior knowledge of CSS from you. The only prerequisite is to take your time to do practice and follow along all the examples. It begins from very simple example and that same example carries through the entire book while it teaches more detailed and complex concepts gradually. Before you know, you will have a fairly good understanding of CSS3, Responsive Web Design and some of the advanced concepts such as flexbox.On the flip side, I really wish author would have added couple of appendix on different CSS selectors and CSS specificity. That would server as a reference guide to at my desk and I could refer to them as and when needed.

There are a number of grammatical errors, some of the advice is outdated, other advice is just plain wrong. Much of the book is geared towards a novice, which might forgive some of the statements, but other statements are laughably wrong.- He calls using ID's and class names "renaming" elements. Renaming an element is changing a div to an article. What he's doing is changing the selector or specificity.- He references pseudo classes without explaining what they are (there is a vague reference to how they're used three chapters after he uses the first one).- He talks about IE7. That's not a thing anymore.- He confuses convention (calling things clearfix) with purpose (clearing CSS float property).- He advocates non-semantic CSS as a solution to the problem of non-semantic HTML- He (arguably) conflates anchors and buttons- The specificity "points" concept does not work the way he says. If you have eleven CSS classes in a selector that will not override one ID. (He does clarify this about two chapters after introducing the idea, but he's been using incorrect nomenclature the entire time.)