In 1993, Kelly and Power showed that the category of finitary monads on a locally finitely presentable category A is of descent type over a power of A; here we establish the stronger result that the forgetful functor in question is monadic. Both their result and ours remain true in the V-enriched case for suitable monoidal categories V. Generalizing further, we obtain a monadicity result for algebras for an operad.
The entire paper is available electronically in preprint form.