BURLINGAME, Calif.

There are no one-handed push-ups or headstands on the yoga mat for Gordon Murray anymore.

No more playing bridge, either — he jokingly accuses his brain surgeon of robbing him of the gray matter that contained all the bidding strategy.

But when Mr. Murray, a former bond salesman for Goldman Sachs who rose to the managing director level at both Lehman Brothers and Credit Suisse First Boston, decided to cease all treatment five months ago for his glioblastoma, a type of brain cancer, his first impulse was not to mourn what he couldn’t do anymore or to buy an island or to move to Paris. Instead, he hunkered down in his tiny home office here and channeled whatever remaining energy he could muster into a slim paperback. It’s called “The Investment Answer,” and he wrote it with his friend and financial adviser Daniel Goldie to explain investing in a handful of simple steps.

Why a book? And why this subject? Nine years ago, after retiring from 25 years of pushing bonds on pension and mutual fund managers trying to beat the market averages over long periods of time, Mr. Murray had an epiphany about the futility of his former customers’ pursuits.