A super helpful book for not only learning more nuances about tackling, shedding, and coverage techniques, but also the common gap-read and key-reads made by different LB assignments. Definitely the most thorough read I've found of the subject so far, and it increased my football knowledge immensely.
The one addition I wish was more prevalent would be to give more examples of how each LB type (30, 31, 32, 51/52, hawk, mike, etc.) actually fit into common defenses. This book primarily just focused on the author's speciality, the 3-3 along with some 4 man fronts, but I would've liked a deeper dive into what defenses these roles are most prevalent in respectively.