- Vol. 21, No. 4, Issue 159
- Titled Worlds of If Science Fiction on the cover and contents page. Titled If Science Fiction on the spine.
- Cover and spine dated April 1972. Contents page dated March-April 1972.
- UK Price 25p printed on the cover. This issue was distributed in both US and UK.
- Pages number 1-176, not including the covers.
- Cover suggested by "The Gods Themselves" as noted on the Contents/copyright page (scanned version from archive.org).
- Parts One and Three of the serial "The Gods Themselves" appeared in the March and May issues of Galaxy.
- No interior art is explicitly credited. Jack Gaughan's art identified by signature.
- "Patterns of Chaos" is labeled as the 'Conclusion' on the title page of the installment but is actually concluded in the next issue.
The full text and images of this edition are available at The Internet Archive, see web page for link.
