18...Kxf7 19. Qc4+ Kf6 20. Bg5+ loses the Queen.

Here's what is actually written in OMGP II at p. 161 (Kasparov is quoting Lev Alburt, who was three years old in 1948 and has no more first hand knowledge of the facts than you or I, but has written some crazy @#$% about Soviet players).

<On the way from the Hague to Moscow, ex-world champion Max Euwe had his chess notebooks confiscated in Brest <(as Botvinnik writes, these were Euwe's secret opening analyses --G.K)>. The customs officials, you see, imagined that this was code. At Botvinnik's request the notebooks were returned, and Euwe was touched and heartily grateful, but...copies of the notes somehow found their way to the Soviet grandmasters.>

Assuming this copying-and-dissemination actually took place, it did Botvinnik no good: he had two quiet draws with Euwe in Moscow, and neither game was played at the bleeding edge of opening theory.

Euwe vs Botvinnik, 1948

Botvinnik vs Euwe, 1948

Keres and Smyslov beat Euwe like a rented mule in Moscow, but they'd done the same in the Hague.

A startling claim, which I'd never heard anyone make before. Not crazy, but startling. (I assume that Lutz meant "greatest" rather than literally "best," which really would be crazy. As with other competitive endeavors, players continually get better, and it is certain that Kasparov, Karpov, and Fischer among others were stronger in absolute terms than Botvinnik.) Almost everyone would rate Kasparov and Fischer higher. I would add Lasker to that list. Many would add Capablanca (certainly Chernev would, since he claimed for some reason that Capa was the greatest).

It's probably unfair, but I mostly think of Botvinnik as the world champion of exploiting rules written to favor him. He won the FIDE World Championship Tournament (1948) handily, but he <never> won a one-on-one match <as world champion>. He drew Bronstein in 1951, drew Smyslov in 1954, lost to Smyslov in 1957, won the return match in 1958, lost to Tal in 1960, won the return match in 1961, and lost to Petrosian in 1963. By this time, FIDE had taken away his right to a return match, so Botvinnik took his ball and went home in a snit. In those seven matches from 1951 to 1963 he scored minus 3. Ties in 1951 and 1954, -3 in 1957, +2 in 1958, -4 in 1960, +5 in 1961, -3 in 1963. Yet with this record Botvinnik was world champion for all but two of the years from 1948 to 1963! This strikes me as very unfair. Smyslov won two consecutive Candidates tournaments - something Botvinnik never had to do - and then got a plus score in three matches against Botvinnik. All that work, yet poor Smyslov only got to be world champion for one year.

I have no point to prove here, but believe the above could well have been true and that matters could easily have gone thus; but we shall never know.

I find Lutz' claim hilarious.

I would add Karpov. The contrast between Karpov as champ and Botvinnik as champ is pretty glaring. I think of Capa and Alekhine on more or less a par with Botvinnik.

<Botvinnik fans will protest that he peaked in the early 1940s, and might well have had an even longer and more impressive reign as world champion if WWII hadn't intervened. Could be.>

I do think that's true. On the other hand, it's also possible to write happier biographies for Keres and Flohr if not for Hitler and Stalin. (Though I think Flohr was too much of a beat-the-weakies-with-technique player even at his peak to ever win the title.)

I don't know enough about his biography to say. I've also heard that he had a nervous breakdown after he won the title, though there is probably no more to that than someone noticing he didn't play for three years and concluding "he must have had a nervous breakdown!". He spent a lot of time on chess computers and also had, as <perfidious> noted, a chess school. Could he have done that, played a fair amount of (thoroughly prepared!) chess and also worked full-time as an engineer or scientist?