Which builds up from first principles a ballistic missile defence system. Always useful to have.
Here are two favorite readings for anyone willing to delve more into the subject:
Orbital Mechanics for Engineering Students by Howard D. Curtis
https://www.amazon.com/Orbital-Mechanics-Engineering-Student... Fundamentals of Astrodynamics (aka BMW) by Roger R. Bate, Donald D. Mueller, Jerry E. White, William W. Saylor
https://www.amazon.com/Fundamentals-Astrodynamics-Second-Dov...Another great textbook as suggested by musgravepeter in the comments is
Fundamentals of Astrodynamics and Applications by David A. Vallado, Wayne D. McClain
https://www.amazon.com/Fundamentals-Astrodynamics-Applicatio...
Tactical and Strategic Missile Guidance, Seventh Edition https://www.amazon.com/Tactical-Strategic-Missile-Guidance-S...
Tactical missile warheads https://www.amazon.com/Tactical-Warheads-Progress-Astronauti...
Fundamentals of Astrodynamics https://www.amazon.com/Fundamentals-Astrodynamics-Second-Dov...