that: "I want to do my own stuff, my own way". He would go on to write a series of challenging books that redrew the boundaries of science fiction, including Stranger in a Strange Land (1961) and The Moon Is a Harsh Mistress (1966). Later life and death Beginning in 1970, Heinlein had a series of health crises, broken by strenuous periods of activity in his hobby of stonemasonry: in a private correspondence, he referred to that as his "usual and favorite occupation between books". The decade began with a life-threatening attack of peritonitis, recovery from which required more than two years, and treatment of which required multiple transfusions of Heinlein's rare blood type, A2 negative. As soon as he was well enough to write again, he began work on Time Enough for Love (1973), which introduced many of the themes found in his later fiction. In the mid-1970s, Heinlein wrote two articles for the Britannica Compton Yearbook. He and Ginny crisscrossed the country helping to reorganize blood donation in the United States in an effort to assist the system which had saved his life. At science fiction conventions to receive his autograph, fans would be asked to co-sign with Heinlein a beautifully embellished pledge form he supplied stating that the recipient agrees that they will donate blood. He was the guest of honor at the Worldcon in 1976 for the third time at MidAmeriCon in Kansas City, Missouri. At that Worldcon, Heinlein hosted a blood drive and donors' reception to thank all those who had helped save lives. Beginning in 1977, and including an episode while vacationing in Tahiti in early 1978, he had episodes of reversible neurologic dysfunction due to transient ischemic attacks. Over the next few months, he became more and more exhausted, and his health again began to decline. The problem was determined to be a blocked carotid artery, and he had one of the earliest known carotid bypass operations to correct it. Heinlein and Virginia had been smokers, and smoking appears often in his fiction, as do fictitious strikable self-lighting cigarettes. In 1980, Robert Heinlein was a member of the Citizens Advisory Council on National Space Policy, chaired by Jerry Pournelle, which met at the home of SF writer Larry Niven to write space policy papers for the incoming Reagan administration. Members included such aerospace industry leaders as former astronaut Buzz Aldrin, General Daniel O.