If you are reading this, you are starting the journey to get your ISSEP, and I earned my CISSP-ISSAP back in 2018, a requirement for work as a DoD Civilian.
I used the ISC2 self-study course, which was expensive, but the E-Learning Book has content similar to the exam and a practice exam that provides the reason the answer was wrong or correct after you do the practice exam.
The learning course is based on the theme of a security/system engineer in a company, so you get a 360-degree concept of best security and engineering practices.
Kyle
