Some of it brilliantly (by Michael Kandel), some of it woefully. Alas, to
the best of my knowledge, the SUMMA *hasn't* been Englished, which is a
terrible shame. Neither has the full text of his study of sf, although
fragments have appeared (it would now be very dated, of course, and was
based on a tremendously biased and random selection of material available
to Lem in Poland thirty-odd years ago).
Damien Broderick