His last paragraph sums it up quite nicely....

"Hamilton’s discovery that McCandless perished because he ate toxic seeds is unlikely to persuade many Alaskans to regard McCandless in a more sympathetic light, but it may prevent other backcountry foragers from accidentally poisoning themselves. Had McCandless’s guidebook to edible plants warned that Hedysarum alpinum seeds contain a neurotoxin that can cause paralysis, he probably would have walked out of the wild in late August with no more difficulty than when he walked into the wild in April, and would still be alive today. If that were the case, Chris McCandless would now be forty-five years old."