Animations within CSS3 allow the appearance and behavior of an element to be altered in multiple keyframes. Transitions provide a change from one state to another, while animations can set multiple points of transition upon different keyframes.
If things such as @keyframes rule and animation-iteration-count property terrify you, then you might need a simple, more structured introduction to CSS animations.
It's a short book, written in a simple way that has tons of live demos, which really helps you learn the content.
In this book Val covers the basics of CSS animations, walking you through a series of examples, and discussing practical considerations for dealing with browsers and fallbacks. You'll have everything you need to start playing with CSS animations in just a couple of hours.
Part 1: CSS Animation Basics
Part 3: Understanding Easing
Part 4: Common Animation Tasks
Part 5: Performance and browser support
The book is available under a pay-what-you-want model, meaning you can choose what the book should cost to you.
If cash flow is a problem, you can download the book for free.