This could have easily been a thirty page essay as an after thought in Annihilation or an epilogue of sorts. The middle part of the book is plain boring and doesn't offer much to the overall story arc that's being built. Southern Reach is made out to be more complex than it is, shoving Kafkaesque mood setting every now and then, and vigorously shaky reality. 
 It was a semi-enjoyable read as the perspective of narration is completely changed and we get to see the problem at large. Instead of calling Authority a sequel, it should simply be known as a companion piece to Annihilation.