Originally Posted by Xenophon
My memory of the chronology of Heinlein and his medical problems goes about like this:
He was doing fine up until he was part way through writing I Will Fear No Evil. Part way through work on that book he began having medical problems -- the aforementioned restriction of blood to his brain. He managed to finish the first draft and some polishing, but eventually Ginny Heinlein had to send the manuscript off to the publisher in its not-quite-finished state.
Heinlein then didn't write anything for a number of years. Corrective surgery improved his health (eventually). Time Enough for Love was his first book post-surgery.
Someone with more fannish knowledge will surely correct me if I'm wrong.
Heinlein was Writer GoH at MidAmericon, the World SF Convention in Kansas City in 1976. He had had bypass surgery at that point, and told the crowd about it, saying "I feel great!" There had been a four year gap between _The Moon Is a Harsh Mistress_, appearing in 1966, and _I Will Fear No Evil_ in 1970. _Time Enough for Love_ appeared in 1973. _The Number of the Beast_ appeared in 1980.
I wouldn't attribute all of the gap to health problems. Heinlein had reached a point of financial security where he didn't necessarily have
to write to keep food on the table. Just about everything he'd written was in print and generating royalties.
He could write when he felt like he had something to say.