It's a great book, worthy of all the attention it's getting. I don't have a coherent assessment or review, but here are some disorganized thoughts about the book, in no particular order...
Despite never discussing Heidegger, this is essentially a Heidegger book. The themes are all there: finitude; an ethics of care; the human being as the one who questions after its own being; our relation to death; an orientation toward time ("the secular"). Surprisingly there are only two or three references to Heidegger, all in footnotes, one note divulging that Hägglund's next book will explicitly address Heidegger's Being and Time.
The book has a very "Western Civ" vibe. I can imagine someone teaching This Life in the undergraduate core curriculum at a place like Yale (where Hägglund teaches). He's got all the hits: the Bible, Saint Augustine, Kierkegaard, etc. I got whiplash when Hägglund segued straight from Saint Augustine to Karl Ove Knausgård. But he made it work somehow.
Hägglund addresses big ideas. What makes a life worth living? How and why do we value things? He's all heart, even a bit touchy-feely. But I'm here for it.
Hägglund writes in a clear and direct style, and largely avoids the affectations of both continental theory and analytic philosophy. That said, he is keen on repetition. By the end of the book you will have read his core thesis statement dozens of times: our life is finite; we only value things because we know they can be lost.
I'll admit I don't really get Hägglund's insistence on secularity. Although the soft contradiction of a phrase like "secular faith" has a certain appeal. He seems to want to troll both theists and atheists at the same time.
Some interesting connections might be formed by reading Hägglund's "faith" against Badiou's "fidelity." A meeting between Hägglund and Badiou makes sense in other ways too, given that they both essentially write about subjects. Although they would disagree on the question of finitude; Hägglund pro, Badiou con.
The surprising (but not unwelcome) plot twist is that Hägglund roots a good portion of his argument in Karl Marx. Fun, fun. Although the Marx stuff really only appears in chapters 5-6, and Hägglund's Marxism feels a bit new and awkward, based on his citations and treatment of the sources.
Despite how I appreciated Hägglund's use of Marx, I have sympathy for Jodi Dean's critique of the book. In embracing Marx, she writes, Hägglund in fact does Marx a disservice. Dean puts the problem succinctly: Hägglund repositions value production away from the site of labor, and hence away from a site fundamentally characterized by a political struggle between classes. Instead Hägglund defines value through the existential quandaries of human finitude and frailty. This has the effect of deemphasizing social antagonism in favor of one's personal quest for meaning. (In response to which Hägglund insists that the latter is always already social, which makes sense, but the larger problem remains.) Dean thus nominates Hägglund as "socialism for liberals," which, while harsh, contains a grain of truth. Or maybe it should be something like "socialism for existentialists."
My most generous read is that Hägglund doesn't do injury to Marx so much as sublate or supersede him. Let's not forget that Marx actually wrote very little about real utopia, focusing instead on currently existing conditions. Hägglund's magic is to make these existing conditions the utopian condition itself. And hence liberation from existing conditions would, in fact, entail being more firmly embedded within them. Hägglund's word is "freedom" but he uses the term in a way incompatible with contemporary liberalism, itself so politically stunted by Isaiah Berlin's "negative liberty." Hägglund's freedom is not so much about removing fetters as it is about freely recognizing obligations and responsibilities.
Hägglund has a strange relationship to women. I will let his psychoanalyst try to unravel the following two observations. First, there are virtually no women in This Life. After a quick mention of Rosa Luxemburg near the beginning, the first two women in the book only appear because they are, in fact, dead. I mean diegetically dead; they are the dead daughter and dead wife of two figures he discusses (Martin Luther and C.S. Lewis). Second, most of the authors Hägglund discusses are men who have been conventionally understood as feminized in some way, or who work in a feminine idiom: Saint Augustine, Kierkegaard, Proust, Knausgård, even Christ. In other words, Hägglund's book is structurally femme, yet almost exclusively in the company of men.
It should also be noted that this book is extremely white and Eurocentric. The only real reference to race comes in the form of a brief, formulaic discussion of Martin Luther King at the very end of the book. If you like your scholarship woke, This Life won't do it for you. Or forget woke, if you like your scholarship even remotely cognizant of canon debates since the 1980s, This Life won't do it for you.
That said, I marveled at the technical coherence of Hägglund's narrative arc. He really does travel from the thisness of human existence right through to communism at the end. And there's no hand waving along the way; he accounts for every step, and each step has an intellectual momentum. Much work on the left ends up being dogmatic about its foundations -- you either believe in communism or you don't, you're either with us or you're not. Hägglund has his axioms, but they reside much lower in the stack. The only "dogmatic" principle he begins from is the finitude of human life.
Despite some of the above shortcomings, let me reiterate that This Life is a very good book, one of the major works of philosophy published in recent years. For a quick immersion into Hägglund's work I would also suggest listening to two recent podcasts in which he appears: The Dig and What's Left of Philosophy. Both episodes are excellent.