This book is an excessively philosophical work. There are good points made, but there is a lack of political clarification in favour of abstraction. The philosophising is part of a political problem. If one wants to read a densely political Gramsci-influenced study of revolutionary Marxism, read Alan Shandro's book on Lenin's political thought.
Thomas argues that the Prison Notebooks are less cryptic than often thought. Gramsci's jailers would not have been tricked by wordplay into thinking that he was just writing harmless niceties. The representative words used by Gramsci are more often just notes for abbreviation, as he would have done in any context. Also, it may have been that when Gramsci used a certain term, he meant it over the 'translation', for instance that when Gramsci speaks of the 'philosophy of praxis' he doesn't just mean 'Marxism' but uses this term to refer to something more specific than Marxism.
What the Notebooks are is fragmentary. Though this is not unusual for the Marxist canon. Understanding Marxism materialistically means we have to see its texts not as timeless treatises establishing eternal doctrine. To do so would be a liberal conception of intellectual history. Instead, we have to see them as part of historical development, as concrete interventions. Getting something from them for our own time requires an understanding of context to know the intention of the work, and is determined by the political questions that we face in our own time. It's not illegitimate to read 'into' historical texts meaning which is determined by our own time, so long as we are conscious of the historical determinations involved in such a reading.
Thomas correctly argues that hegemony is not counterposed to dictatorship. It is rather the form of leadership and dominance over those who are in an alliance. From that, force against the enemy of the alliance finds legitimacy. There is a dialectic of coercion and consent: consent is developed through force (power provides reason to support), but force also requires legitimacy to not be seen as an outrage. Often, the relationship is not sequential, but both arise as aspects of a contested situation.
For a hypothetical example: In a mass strike, the state seeks to enact repression, but it also fights to win legitimacy for that repression. 'The people participating in the strike are a minority of society (true!), parliament represents the whole of society and therefore takes precedent.' This is an argument for the legitimacy of the bureaucratic state apparatus over the proletariat. For the proletariat there would be two struggles, first the struggle of the strike itself and the fight against repression, but then also the struggle for legitimacy, that it is not the government but the strike that represents the interests of the people and which the people should get behind. Coercion and consent are in dialectical union. It is never an either/or issue of determining what moment is that of consent or that of coercion.
Gramsci draws on Machiavelli's image of the Centaur, of half man half beast, to make the point: "levels of force and consent, authority and hegemony, violence and civilisation, of the individual moment and of the universal moment ('Church' and 'State'), of agitation and of propaganda, of tactics and of strategy, etc... it often happens that the more the first 'perspective' is 'immediate' and elementary, the more the second has to be 'distant' (not in time, but as a dialectical relation), complex and elevated. In other words, it may happen as in human life, that the more an individual is compelled to defend his own immediate physical existence, the more will be uphold and identify with the complex and most noble values of civilisation and of humanity."
The relationship of civil society and state to base and superstructure is complex. Gramsci certainly does not identify civil society with base and state with superstructure. Civil society has a superstructural aspect, moreover Gramsci emphasises this in arguing that economy must be theorised politically. Conversely the state cannot be understood as an entity without a basic aspect, as Engels argued political power is also an economic power. The structure of civil society is the terrain of political action.
Passive revolution is a concept of particular controversy. More than just a description of bourgeois 'revolutions from above', it is the term which describes the process of rearticulation and reorganisation of the bourgeoisie's hegemonic position, in the face of a crisis of hegemony. It is prompted by class struggle raising itself such that the oppressed classes are threatening a breaking apart of bourgeois political dominance. That the class struggle prompts the bourgeoisie to creatively rearticulate its hegemonic position, that the class struggle in this sense can contribute to the prolonging of capitalism as much as its overthrow, is very important for understanding history up to the present and the crisis of hegemony the bourgeoisie faces today.
Gramsci was neither a Trotskyist nor a Stalinist. He saw himself as forwarding Lenin's political thought. I've commented on the critique of Trotsky elsewhere. Gramsci against Stalin is significant to emphasise when Stalin and Bukharin claimed the concept of hegemony against Trotsky. For Stalin, Lenin's contribution was in the proletarian dictatorship supposedly negating the pre-revolutionary struggle for hegemony. For Gramsci, Lenin's greatest innovation in realising hegemony came after 1917. Hegemony was not counterposed to but complimented dictatorship. Stalin and the Eurocommunists both misunderstood this. Lenin understood totally differently to Stalin the tasks of the government after the civil war, seen in his last arguments against bureaucratisation, which Gramsci draws on in opposition to Stalin. Gramsci's discussion of culture here is significant: one of Lenin's last arguments about the struggle against bureaucratisation was to raise the cultural level of the masses so that they could act as a check on the government.
The weaker parts of the book are the more philosophical sections. Thomas leans on the philosophical category of immanence to establish Gramsci's philosophy of praxis as an Hegelian identity of theory and practice. That Thomas sees in the struggle for hegemony only these concepts is a problem on his part. The scientific aspect of Marxism must be defending to uphold a materialistic approach to politics. Marxism is a science and a philosophy; a science with respect to theory, and a philosophy with respect to practice. This is not to separate theory from practice, but to assert their non-identity. Science is necessary for making an objective assessment of the balance of forces. This is not Marxism as sociology as in Bukharin (which Gramsci in his critique does not totally discard insofar as it makes a scientific contribution), it is a recognition that science does not immediately spring out of practice as Marxist knowledge.
Thomas sees in the conception of Marxism as science a dogmatic religion imposed on workers from outside. This is the inverse of the Althusserian conception of theoretical practice. Both ultimately rest on an identity rather than unity of theory and practice. Lenin's conception of Marxism as being engaged in a struggle with spontaneity is the only coherent way of situating oneself within the historical process without reducing marxism to its object. It is the only way of understanding Marxism as developing through history, that it creatively innovates and doesn't defend a timeless truth. The non-Leninist conception gives rise to a contradiction, of on the one hand Marxism as a god complex viewing history from outside, and on the other hand conceiving of Marxist theory as immanent to its object; Marxism is merely the expression of the logic of the proletariat, and comprehending Marxism is a matter of divination of absolute knowledge. This is a religious conception. Both humanism and anti-humanism are dogmatic, and both have origins on Christian thought. The god complex is philosophically totalitarian for ascribing to everything its own knowledge or the process it interprets. Situating oneself within the logic of the historical process and a conception of consciousness from without are two sides of the same theoretical grounding. Lenin's alternative grounded the conception of agency found in the Marxist concept of leadership i.e. hegemony. By conceiving the role of the intellectual and of the party as pedagogical through struggle, Thomas develops a conception of hegemony more in like with Menshevism. This is the result of believing hegemony to be a primarily philosophical rather than political question. For Menshevism, proletarian hegemony was secured through the proletariat relating to its own activity; such a focus on identity went the way metaphysics, sending the Mensheviks down the path of opportunism and subservience to the bourgeoisie. For Bolshevism, proletarian hegemony is secured through a particular relationship of the proletariat to other classes and social strata.
Thomas sees too much in the united front. While it was greatly significant a question in Gramsci's time, it should be elevated to a strategy. The united front was at an important but nevertheless tactical difference with the Stalinist third period. The political problems ran deeper than that. It is an economism which sees the united front as a strategy, focusing on the self-contained working class in relationship with itself. United Front as strategy gives way to tailism. The point of the united front tactic, a move specific to workers' parties, was to put the workers' movement from the defencive onto the offensive so that it may then go on to win leadership of other classes. There are two levels of hegemony: that of the Marxist party over the proletariat, and that of the proletariat over other classes and the people as a mass. These are secured simultaneously, and missing one means you get neither. The active role that the party plays in articulating a strategic alliance of class forces is missed, and therefore the party is downplayed. Thomas' political suggestions at the time were ultimately socialist-movementist, such as calling for militancy in the trade unions. That's well and good, but it's not enough of an orientation in itself; it doesn't clarify the specific role of Marxism in a strategic orientation to working-class power. The contradiction of anti-party and anti-revolutionary party attitudes of the left today will only be overcome by dedicated effort informed by more than the arguments of this text.