Just finished reading this short but fairly in depth book about Robespierre. If you have knowledge of the classics (Roman and Greek) then this book is for you. The author stresses how Robespierre was heavily influenced by the studies he had done of Roman and Greek history (as where many politicians during the Renaissance). he does quote alot of Robespierre's speeches and if you don't have knowledge or interest in the classics, you may not enjoy it as much as I did.
The book is, in my opinion, fairly balanced but the author seems to be an admirer of Robespierre...he sort of defends the "Terreur" and Robespierre's use of the guillotine during the later par tof the French Revolution. I read it in French, not sure if it exists in English.