This guide covers a VA disability claim from the first filing through judicial review. Part 1 sets out the three structural rules that make this system unlike any other benefits system. Parts 2 and 3 cover the elements of service connection and the nexus opinion that decides most claims. Part 4 covers the presumptions. Part 5 covers the four alternative theories, including the secondary claims that are chronically under-filed. Parts 6 and 7 cover ratings, individual unemployability, and the ancillary benefits. Part 8 covers effective dates after Arellano. Parts 9 and 10 cover evidence and the three appeal lanes. Parts 11 through 13 cover mental health claims, judicial review, and practice notes by role.