New answers tagged authorship
The Rebbe didn't actually write many seforim. He wrote hayom yom in the name of the Friediker Rebbe and a Haggadah (and I think he also wrote a biography of the Rebbe Maharash). igros kodesh is from his letters, which I think some were written by him and some were dictated to the secretary. The rest is from his sichos (speeches) and ma'amorim (chassidus ...
Does he have the most published seforim out of all gedolim? Many of 'his' books are (near-)transcriptions of what he said, in many cases not even corrected by him ("בלתי מוגה"). Since God taught the complete explanation of Chumash (plus some other stuff) to Moses at Sinai, the gadol with the most published books is הקל הגדול.
On Hebrewbooks i made a search (of scanned books) for author שניאורסון, מנחם מנדל, 1902 I get 322 (some of them have the same sicha/maamar/point printed in 2 different books (sometimes translated differently or just in different orders))
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