Michael

This book has a 5-star concept. There are echoes of Blake Crouch, the Severance TV show, and even Lost. The character works for a hyper-secretive company named Langan, and the president at the time is Whitmore -- how can I not think of Severance's Lumen and Lost's Charles Widmore?

Although the promise of the time travel conceit meant that I couldn't put it down, the first two-thirds were slow, and everyone and everything outside of the main character felt underdeveloped. The last third significantly picked up the pace and reached a satisfying conclusion, even though it's not exactly how I would have preferred it to end.

The Great When is a tough book to recommend. At times, the complicated prose transported me to the alternate London the characters inhabit. But most often, it was so dense and inscrutable that it greatly detracted from my enjoyment. The plot picks up in the second half, but I didn't necessarily like the sudden shift in the conflict's focus. I wish we spent more time with (or in the heads of) some of the side characters, as it sometimes feels like this book pitches a series rather than commits to one, like a TV show afraid it won't get picked up for a 2nd season.

Three things I wish I had known before starting this book (in no particular order; also, these are my opinions and not facts):

• While the plot and world-building are intricate, they prioritize style over substance.
• There are a lot of interesting side characters whose personalities shine in the scenes they are in, but they are their personalities and not as developed as I would have liked.

The main character is young and immature, and some of the "immature" scenes feel unjustified. Spoiler example: he fawns over a sex worker that he thinks is 25, but she turns out to be 15 for no reason other than "man, times were rough back then, huh?"