Sylvia Mackey regards Blazing Trails as a legacy for the public, so that people "know how instrumental he was in making change," as well as for her family, which includes two daughters and a son, all grown, and five grandchildren.
For all it does cover, Blazing Trails does not refer to Mackey's disease, and only his closest friends and family have known of his illness.
"Here is a fellow who five years ago was a different person," says Pete Wright, a corporal with the Howard County Police Department who frequently chaperones Mackey to autograph sessions. "Now, he's more in the past."
A slow deterioration
The Mackeys believed life after football would be quite different.
Indeed, it was at the beginning.
Upon retiring at the end of the 1972 season with the San Diego Chargers, John Mackey was involved with several business deals, and Sylvia was a successful model, providing the couple with a comfortable if not lavish lifestyle in California.
Slowly, though, Mackey grew indifferent to his business relationships and the family's finances, until he neglected them altogether. The family increasingly depended upon the money Sylvia earned as a model and in commercials.
Among those she modeled for were Vogue magazine and the catalogs for Sears and J.C. Penney. She also appeared in numerous commercials for McDonald's, Nestle Tea, 7UP and communications giant AT&T.
The money was good but not dependable, ranging from $90,000 one year to $11,000 in another. Nor did modeling and commercial work provide benefits, like medical insurance.
Sylvia Mackey at first tried nudging her husband. "I said, 'What are you doing?' And he kept saying, 'Oh, I'm going to a get a job.' "
He never did, so five years ago, at the age of 57, Sylvia Mackey began a second career as a flight attendant for United Airlines to help make ends meet.
It was at this time that her husband's behavior began changing more noticeably: John Mackey's memory was fading; he was often lethargic; and when he was busy, it usually was with the trivial.
One day Sylvia Mackey returned home to find her husband anxious to show off a tiny shelf he had constructed.
"I'm thinking a big businessman like you doesn't get a joy out of putting this little shelf together and showing it to me like he's so proud," she recalls. "It really wasn't cute, or pretty or anything."
Another, more troubling, trait was also emerging: John Mackey's tone became threatening -- "violent" in the words of his wife. Those eruptions for a time severed the relationship with his youngest daughter, Laura, now 35.
"He used profanity. He called me a bitch," she recalls. "I wouldn't stand for it from anyone. I was shocked that he would use that type of language with me, because I was always the baby to him."
She didn't speak with her father for two months.