This is one of those books that kept coming up on book lists and reviews. It's hugely popular, so I thought I'd give it a try.
The technological conceit of this book is personality uploading. Bob is super-rich and buys a cryogenic preservation insurance policy. It's not a spoiler to tell you that, surprise surprise, he ends up needing it. He lands in a dystopian future, denuded of all his riches, and quite literally the property of a religiously zealous government. What ensues is a novel based on Bob becoming the heart of a Von Neuman probe (self-replicating, galaxy exploring).
As is hinted at by the title, the tone is very light. Even the darkest bits of the narrative, which aren't particularly dark anyway, aren't very affecting. That's not a complaint, but in terms of your emotional engagement with this book, don't expect intense emotion or drama. Expect a light-hearted, safe romp.
Since the nature of these probes is to be self-replicating, over time Bob builds more of himself--hence the legion bit in the title. By an unexplained quirk of the technology, none of Bob's clones is exactly Bob. They're all Bob variants. That makes for some fun self-loathing bits.
The Bobs are smart, funny, nice guys that constantly make late 20th century cultural allusions. For instance, one uses Homer Simpson as his avatar. One names himself Riker after the ST-TNG character. In that sense, these books have a Ready Player One flavor to them. It constantly mines those cultural references to good effect. Eventually it got old to me.
Because all the Bobs are shades of the original, it didn't hurt much to see a few of them get destroyed. There is never a situation in this book where there is real jeopardy for Bob or his interests. There is very little conflict or resolution to speak of. With all their computing cycles, the Bob's never invent anything more than some of the very old sci-fi standards like FTL communication. That is, even with years of inter-stellar travel time, the Bobs don't evolve in interesting ways.
Plot wise, this book in the series sort of focuses on what happens when one of the Bob's goes back to Earth. I say sort of because that sub-plot is one of many. The book bounces between Bobs with each chapter. Chapter headings list the Bob variant that serves as the POV character, his location, and the date. So the book, rather than one coherent story, is really a collection of Bob vignettes broken into pieces. By doing this, the author has robbed us of a lot of the fun of a strong novel. There are no great story arcs or character arcs. It really is more like a collection of linked short stories.
My point is that although the multiplicity of Bobs is cute, it got old quickly for me. The inter-Bob banter got stale. The technology likewise was boring. For instance, the only weapons he builds are ballistic masses (fast moving things that destroy via kinetic energy), both for ship battles and on planets. We never get anything innovative, it's just Bob-as-fanboy getting to build some of his sci-fi favorites. The plots, likewise were stale to me: simplistic ship battle, simplistic first-contact, simplistic refugee politics. In the end, everything works out. To me it was the afterschool-special of sci-fi.
I won't finish the series because I'm not that interested in where this author will take things. From the title of the third book, I can make a pretty good guess.
It's extremely popular, so I seem to be in the minority. This book simply didn't appeal to my taste. If you want a breezy, upbeat, quick read that evokes a lot of cultural nostalgia, you could do a lot worse.