Paul Wells 
Basics Animation 01: Scriptwriting [PDF ebook] 

Basics Animation: Scriptwriting addresses the full range of approaches to scripting and developing for animated films.
It details the issues faced by the animation scriptwriter, and the techniques to overcome them. It also seeks to promote the unique qualities of animation as a form of expression, using many images to illustrate and emphasise points made in the text.
This book looks at genres in animation as a starting point for scripting, employing a range of case studies from feature films to public relations work to independent productions, in order to reveal a range of approaches to writing.