Grant writes very movingly about Joan's diagnosis, his own fears and anguish, as well as Joan's own decline. He doesn't gloss over the practical and emotional difficulties of her last months and days; always sharp, she becomes irritable, demanding and irascible and even Grant, who clearly worships the ground she walks on, finds this very challenging and exhausting. They are wonderfully supported by their many friends (though Grant also points out, without naming them, that there were some 'friends' who fell by the wayside), and their grown up daughter Oilly and her partner are also an amazing source of strength.
Interwoven with the sadness of Joan's illness are plenty of happy and funny memories of their time together, and lots of movie and celebrity anecdotes, which I suspect some people will primarily read the book for (like Grant's account of appearing in Star Wars and Loki, neither of which are of huge interest to me -- I was more interested in his role in Persuasion!) But for me, the diary of Joan's last days was extremely moving and in some ways reassuring. This is an experience that almost all of us will need to undergo at some point, and I welcome all the reports from the front line that I can get.