Note: There are other series with the same name: Worlds of If (relaunch)
- Series: Worlds of If (If) Series Record # 24569
- Worlds of If (If)
- Worlds of If (If, September 1959) (1959) [ES] by Frederik Pohl
- Worlds of If (If, November 1959) (1959) [ES] by Frederik Pohl
- Worlds of If (If, January 1960) (1960) [ES] by Frederik Pohl
- Worlds of If (If, March 1960) (1960) [ES] by Frederik Pohl
- Worlds of If (If, May 1960) (1960) [ES] by Frederik Pohl
- Worlds of If (If, July 1960) (1960) [ES] by Frederik Pohl
- Worlds of If (If, September 1960) (1960) [ES] by Frederik Pohl
- Worlds of If (If, November 1960) (1960) [ES] by Frederik Pohl
- Worlds of If (If, January 1961) (1961) [ES] by Frederik Pohl