Barrage is a collection with artworks by Rei Hiroe, who is best known for his still-running popular manga, Black Lagoon, which also earned an anime adaptation divided into 2 seasons. Besides Black Lagoon, Rei Hiroe also created other small manga, several NSFW doujinshi and created the concept and character designs of the anime Re:Creators.
Rei Hiroe's has a great artstyle for drawing women, they all look mature, very badass and nicely drawn. However Black Lagoon, being his most famous work, has not many artworks; there's only approx. 27 pages. Other artwork that you will find in the art book is from his other series and other franchises like Fate/Stay Night. The last many pages of the art book (more than half!) is a complete manga (4 chapters) drawn by Hiroe Rei: Phantom bullet.
As a result the art book is not really worth it if you want to buy it for Black Lagoon, it also feels really random to find Fate/Stay Night artwork; there should have been more artwork of his most famous work Black Lagoon. Having a complete manga in the artbook also feels really lazy to fill up the art book with pages, therefore there's not that many artworks in it, which is very unfortunate because his Rei Hiroe's artworks is really awesome.