Firefly’s early demise left fans with a deep sense of loss and plenty of unanswered questions. From what was wrong with the pilot to what was right with the Reavers, from the use of Chinese to how correspondence between Joss and network executives might have gone, from a philosopher’s perspective on “Objects in Space” to a sex therapist’s analysis of Inara, Finding Serenity is filled with writing as exciting, funny and enthralling as the show itself.