This book contains two books written by Antonio Negri in a span of 20 years. Negri was involved in the Italian far left Operaismo and Autonomia movements and is deeply inspired by the philosophies of Marx, Deleuze/Guattari and Spinoza.
The first book - 'The Constitution of Time' is written from a Marxist materialist perspective. It starts with the aporias of time in Marx's works, especially 'Capital', 'Grundrisse' and 'Theories of Surplus Value' such as between intensive and extensive labour time, or between the time of historical materialism and subsumed labour time as values in economic circulation. Negri distinguishes three kinds of time in the subsumed time of captialism - collective, productive and constitutive. In each, he distinguishes a concept of time that is oriented to control and another that is oriented to freedom. Finally, he distinguishes positive and negative variants of the 'time for revolution'.
His aim is to lay the foundation for a time of resistance in a world of control. However, his Deleuze/Guattari borrowings and his dogmatic materialism mar his first book. The first book also suffers from an excess of assertoric rather than logico-analytical statements.
The second book - 'Kairos, Alma Venus, Multitudo' represents a real breakthrough in the philosophy of time. Written 20 years later it represents greater intellectual clarity and helps understand the previous work.
Negri says that time is always the tip of the arrow that has been released. Accordingly, being is always in a state of transformation. Past is a psychological construct and so is future. Neither past or future is experienced time. Time as becoming, as tip of the arrow - is neither past nor future but a time when being transforms itself by inaugurating the new or 'to come'. He also criticizes the focus on being and neglect of time in ontology and launches an attack on spatial metaphors of time which represent time as a sort of plane with past, present and future arranged in a line.
He then goes on to explain other concepts like language, love, multitude, power etc. based on his concept of an ontology grounded in time. This second book is remarkable for the step by step way it builds up its arguments.
Despite his strong anti-Hegelianism and rejection of 'dialectics', he uses a very dialectical method of developing his own arguments , in both books. But, that is one of the strengths of the books and not the soruce of their weaknesses.
His weaknesses lie elsewhere. His materialism and his Deleuze/Guattari heritage, leads him to resort to contortions in order to deal with the question of subject and resistance - because like all materialists he seeks to avoid questions about consciousness and will and like post-structuralists he is uneasy with the question of the 'subject'. However, unlike Deleuze/Guattari he does not bypass the question of the subject by reducing living beings to desiring machines or in any other way, but comes with as good an explanation of the concept of 'subject' as is possible from a strictly materialist perspective.