Hello
There are so many biographies of economists that one is embarrassed
either to mention those of celebrities (Smith/Keynes/Marx/Schumpeter) or
to mention those of long forgotten economists.
Let me mention a biography of a French historian of economic thought :
Marc Pénin Charles Gide 1847-1932 L'esprit critique L'Harmattan Paris 1997
Marc founded the Association Charles Gide pour l'étude de la pensée
économique (the French society for the history of economics)
I mention Gide's biography for it own sake but also because it was
published as a part of a project of collected works. Such projects
usually include one or several biographical notices that are "book
length" (I think to Walras, or JB Say in this context).
best
AA