I can't really add anything to Richard Carter's excellent obit of the man and Karen's comments on the wonder that was Richard Keynes' study*. So I'll add an anecdote.
In a previous life I was skipper of a sail training boat in Northern Ireland (a 56' Ohlund aluminium ketch that sailed like a witch for anyone interested in the details).
One of the few books in my cramped skipper's cabin was Richard Keynes' Fossils, Finches and Fuegians, his superb account of Darwin's voyage of the Beagle and its consequences. If you haven't read it, do try to track down a copy.
After a hard day trying to get a bunch of often arsy teenagers to love sailing in the boisterous Irish sea and fixing the boat as it fell apart around me, reading Darwin's cramped and seasick privations on the Beagle put my relatively comfortable seagoing life into perspective.
Until a certain lanky, charming Northern Irish lad (let's call him Eamon) came aboard and while off watch picked up Fossils, Finches and Fuegians and started reading. And didn't stop. 14, he had shown no interest in either science or history but something about Richard Keynes' book grabbed his tripes.
For the next two days has was all but useless as a crew member as his nose could not be removed from the book. He was utterly absorbed, and kept finding me to read extracts. He brought it into the cockpit to read when he was on watch (well he tried to...), he read it while walking around the boat. While on a lively passage from Campbelltown in Scotland to Belfast the boat fell off a wave and Eamon measured his length on the saloon floor with a crash, the book pressed between his stunned face and the heaving deck.
At the end of the voyage he gave me the book back, saying he'd try and buy one because he wanted to finish it. Well, I couldn't let such an obvious seed go unwatered, so I told him to wait a few days and emailed Randal Keynes, one of Richard's sons.
He told me that his father would be delighted to help and a few days later I was able to post Eamon my copy of Fossils, Finches and Fuegians inscribed to Eamon by the author along with a wonderful personal letter encouraging Eamon in his interest in the voyage and science generally.
I later met Richard Keynes along with my Beagle Project colleagues and he was every bit as much of a gentleman as his prompt and personal reply to my request suggested. His work on Darwin's notes and correspondence mean that those of us with an interest in Darwin's work can go right to the source.
We, those of us who value Darwin and his work, owe him a great debt. The world was better for his being and is lessened by his passing. One of the great shames of Darwin year in 2009 was that despite several requests HarperCollins declined to reprint Fossils, Finches and Fuegians. A great pity since no biology class and lab in this country should be without a copy. Who knows how many more Eamons might meet Richard Keynes' great grandfather through its pages, and fall in love with science or want to step aboard a boat and explore the great inner space of our oceans.
* Karen despite her protestations, behaved perfectly well in Richard Keynes' study. I, on the other hand, did just gaze around at the first edition books and original prints like a slack-jawed imbecile.