Triad
Omnibus 1959 230,000 words
Contents
The World of Null-A 1945

1948 version

The Voyage of the Space Beagle 1950
Slan 1940

1951 version

English
1959 May SF Book Club
hardback code: ? 527 pages $1.90

cover art by
Lew Glanzman

First edition

Reprinted many times, dates unknown.

The cover art is a slightly altered black-and-white cut-out section from the Simon & Schuster edition of The Voyage of the Space Beagle.

Cover image: Axelsson Data: ISFDB