Reddit mentions of Designing Great Beers: The Ultimate Guide to Brewing Classic Beer Styles

I'd start by tweaking a recipe from Brewing Classic Styles or Clone Beers. Then read Designing Great Beers somewhere down the road.

As for designing your own recipe - pick a style you like, then do some research on it by reading it's respective chapters in Designing Great Beers by Ray Daniels and Brewing Classic Styles by Jamil Zainasheff and John Palmer (other sources are great as well, those are the two I most often go to).

My first step is always decide what style I'm aiming for. I reference this book pretty frequently, as well as cross referencing multiple recipes online for my target style to see what has worked well for others. I usually try and keep things as simple as possible, usually no more than 3 or 4 grains. Then it's just iterate and revise until I like it.

This is a good one

I have seen this book in every brewery I've worked in. It's a great resource. Can get a little technical at times but overall it's a book you'll keep going back to.