500 Вђ“ 611 An...: Fantastic Four Vol. 3 001 Вђ“ 70
The range of issues you've noted——represents a significant era of Marvel's "Legacy Numbering" history. In this period, the series shifted from its third volume back to its original 1961 numbering once it reached a milestone. Fantastic Four Vol. 3 Overview
: This stretch included the return of the team to the main Marvel Universe, the introduction of Valeria Richards , and the high-stakes "Unthinkable" arc involving Doctor Doom . The Numbering Jump : the introduction of Valeria Richards
When Vol. 3 reached issue #70, Marvel recalculated the total number of Fantastic Four issues published since 1961 (including Vol. 1 and Vol. 2). often called the "Heroes Return" era
This volume, often called the "Heroes Return" era, launched in after the Onslaught event. Issues #1–70 (1998–2003) : the introduction of Valeria Richards