First and Only
Dan Abnett is, perhaps, my favourite of Black Library's authors and the Guant's Ghosts series was legendary amongst 40k fans even when I first got into the game. First and Only is not only the first novel in the series, but also Abnett's first book as well, so it was rather strange that I had not read it until now.
The experience proved very interesting, as all of the elements that make Abnett's novels so much better than the average pulp military sci-fi were there, only in half-realised form. The writing is a little clunky at times, and some of the supporting characters more wooden than his later work, but the main features of having protagonists that are actually interesting and half-way relatable were present even this early in his writing; as was a plot that felt a little deeper than merely a series of dramatic vignettes and heroic last stands - no space marines being noble and superhuman here.
Overall, First and Only was far from the best book I've ever read, and not even up to Abnett's later standards, but it was nice to see many of the features that would later characterise his writing present and to read a 40k story that wasn't just genetically engineered super soldiers being heroic and black and white morality.