I’ve got a soft spot for “Dialectical and Historical Materialism” (though I can’t claim I understand it all), but I remember liking the letter where he admonishes a comrade for calling themself a “Stalinist”. I wish I could remember which one that was!
I like his writing style, and the way he lays his points out. There’s still a lot in the archive for me to read!
On the Death of Lenin
A moving speech and eulogy, from a man who loved his comrade, who he had fought alongside for many decades.
Also a very large fan of the interview with Stalin by H G Welles.