Quoting from my own website:
In 1985, Pocket Books published Della Van Hise's novel Killing Time, then withdrew it from publication. The wrong draft of the novel had been printed. Pocket had the correct version in the stores pretty quickly, but didn't publicize the change. Van Hise was apparently active in the "slash" fan fiction scene (i.e., fiction about Kirk and Spock as lovers), and she worked a slash subtext into this novel, more overtly in the accidentally printed early draft. The editor at the time had Van Hise rewrite the book to get rid of that subtext. The revised version was used for later printings.
There are at least fifty changes from the first version to the revised version, some as short as a single word, others as long as a paragraph or two. Most of the excisions involve scenes in which there is physical contact between Kirk and Spock (for example, describing the warmth of Spock's hand on Kirk's face during a mindmeld). But there was also a sentence that described Spock's realization that Kirk was the person Spock was meant to spend his life with.
If the cover has raised letters for the title, it's likely to be the original; if not, check anyway, because at least some copies without raised lettering have the unexpurgated text. Better yet, just check page 41 for a passage that begins, "I understand that you were probably playing with dolls and wearing lipstick until you were twenty!" That appears only in the original.