The Walter/Wendy line is not as clear as people like to think. SOB is the first full length Walter Carlos record, so while it was before surgery, she was already living as Wendy while releasing music and making public appearances as Walter. Far more interesting here is that the R2R box uses an alternate version of the cover photograph, the musician is standing on the LP cover. Also the funny thing about that cover is that nothing is patched on the synthesizer, so it wouldn't make a sound. It appears that there might be a patch in the version shown here.
