(4.5 stars.) The Notebooks are among the best nonfiction written in the twentieth century -- similar to Orwell's diaries covering the same years but significantly better.
In short, an Old Bolshevik -- who also happens to be a solid but not-world-class poet and novelist -- somehow escapes Stalin's purges in the mid-1930s, flees to Mexico via transatlantic voyage, and spends 12 years writing near-perfect nonfiction in a series of notebooks, which consist of:
-- 20% belletristic descriptions of Mexico (daily life, Toltec temples, bullfighting, etc.), which are insanely good;
-- 15% poetic/philosophical reflections on a wide variety of topics, which are very good;
-- 15% standard diary entries about his interactions, life, family, etc., which are very good;
-- 10% play-by-play descriptions of WW2 as it happens (+ wildly inaccurate predictions about the post-WW2 liberal order; Bolsheviks aren't exactly known for their deep understanding of society or human nature), which are very good;
-- and then, unfortunately, his main preoccupation and the primary weakness of the work, 40% inside-baseball stuff about internecine conflicts among Communists/Socialists etc., splinter groups of Bolsheviks, GPU spies, etc.
Some of these latter entries, particularly his reminiscences about the October Revolution, Trotsky, etc., are quite interesting, but a fair amount of it drags, and NYRB really needed an editor to take a firm hand and improve the work; no one on earth wants or needs to read Serge spending five pages figuring out which tiny-circulation socialist newspaper should publish his latest polemical article.
And yet, somehow, even in these passages, Serge is often compelling, probably due to the fact that he is an impossibly interesting person who knew, apparently, every famous writer in Europe -- there are priceless first-hand accounts of Zweig, Breton, Gide, Weil, Mandelstam, Blok, Gramsci, Gorky, Bely, Levi-Strauss, St.-Exupery, Bergson, et al., and every Communist of note, including Trotsky, Lenin, and Stalin -- and he never expresses himself in a lazy or secondhand way.