I'll add to what Martin says.
Read the final chapter of “History and Class Consciousness.” Where political freedom was once “light and air” for the labor movement, as Engels, Kautsky and Lenin all understood, freedom in any bourgeois society was now merely, in Lukács’s words, “the freedom of the individual isolated by the fact of property which both reifies and is itself reified.”
To consciously desire the communist “realm of freedom” now necessarily means “consciously taking the steps that will really lead to it...It implies the conscious subordination of the self to that collective will that is destined to bring real freedom into being and that today is earnestly taking the first arduous, uncertain and groping steps towards it. This conscious collective will is the Communist Party”—the vessel of the “true,” imputed consciousness of the proletariat. Only “the discipline of the Communist Party, the unconditional absorption of the total personality in the praxis of the movement, [is capable] of bringing about an authentic freedom.”
There's a term for this: bureaucratic centralism. Lukács provides ideological, philosophical justifications for “iron proletarian centralism” that move beyond the primarily practical, ad-hoc justifications made by the early Communist International. As a result, “Leninism” (a term only coined after Lenin's death, and which should be distinguished from Bolshevism as it was before the Russian Civil War or even before the ban on factions in 1921) becomes a theory of how the working class can never reach revolutionary class-consciousness without a monolithic, militaristic Communist Party intervening “from without.” What was never actually true about “What Is To Be Done?” is very much true about the final chapter of “History and Class Consciousness.”
Lukács' biography of Lenin merely expands upon that final chapter. And in practice you can see what advocates of bureaucratic centralism like John Rees and his co-thinkers take from Lukács.