Just finished reading this book by Nigel Hamilton. He describes the process of writing a biography as arduous yet do-able. He talks about ethical issues (your subject does something bad that you cannot ignore, but people's feelings are hurt), structure, and mechanics. 

He describes five elements of a biography: the life-line, plot (yes, in a biography), search for truth, selection, and story-telling--applied to biography, autobiography, and memoir.

Now who would I want to devote a few years of my life to studying and writing about?