Thanos: Titan Consumed by Barry Lyga is a great concept for a book. The book follows the titular purple titan Thanos, as he journeys all across the universe after his exile from his home planet long before the events of Infinity War. The biggest revelations from the book are how he came to the conclusion that his plan in Infinity War was the right one to save the Universe. Most fans of the Marvel movies only watch the movies so getting a little more context and background on the ultimate villain is nice, but that's about all the value the book adds. It's not as if it's actually bad, it just has a tendency to have some awkward, stilted language in parts and a plot that is slightly undermined by his story in "Avengers: Infinity War" spoiling the first part of the book. Regardless, it's an inoffensive book that is a fun read for fans of the MCU so it might be worth picking it up just because of that. Even if you aren't a fan it's a fairly easy read with some cool Sci-Fi storytelling so it still might be worth giving it a look if you're not a Marvel fan.
NOTE - I wasn't sure how to fit this into the actual review but this book is not actually canon to the movies, but it doesn't seem like we'll be getting anything in the canon really fleshing out this time in the Mad Titan's life so it still has some value as a fun little extra for hardcore fans of the movies.