David Sparks has released his latest in his Field Guide series - Markdown ($9.99 in the iBookstore). (Previous books in the Field Guide series include Paperless and 60 Mountain Lion Tips).
This book demystifies Markdown, making it easy for anybody to learn. This book includes 130 pages and 27 screencasts totaling more than one and a half hours of video. This book will take you from zero knowledge of Markdown to being a Markdown pro and change the way you write for the better.
I write in Markdown on this blog. I use it when I record notes for podcasts I record and when I'm taking notes in conversations for my day job. It's so quick to write when you work in a web/real world hybrid like I do.
There's the version in the iBookstore and there's also a PDF version available if you're not a iOS user.
[gallery type="tiled" ids="21292,21293,21294,21295,21296"]