How does it compare with Applebaum's Gulag?

Applebaum's book is the standard scholarly history, backed by years of archival work and wide critical review. This is a shorter, self-published survey that covers similar ground; choose it for a quick overview, not for citation-level research.

Is it a memoir or a history?

It is a history. The author draws on survivor testimonies and personal narratives, but the book is structured as an account of the camp system, not one person's experience.

Does it cover the camps after Stalin?

The description promises the system's lasting impact on survivors and Soviet society, which implies coverage beyond the Stalin years. The depth of that later period is not stated.

What reading level is it written for?

It is aimed at general readers rather than specialists, judging by the survey format and single-volume length. Expect an accessible narrative rather than dense academic argument.