THE FOURTH OF MAY: Killings and Coverups at Kent State, by William A. Gordon, Prometheus Books, 243 pages, $21.95.

In the spring of 1970, Americans had had enough.

The Vietnam War was dragging on, and unrest on college campuses were becoming increasingly violent. Americans wanted both to come to an end.

“If it takes a blood bath, let’s get it over with. No more appeasement,” then-Gov. Ronald Reagan said of student protests that April.

The symbolic end to the protests came a little less than a month later at Kent State University. A contingent of National Guardsmen, called to the campus to control protests over President Richard Nixon’s decision to send troops to Cambodia, fired into a crowd of students, killing four and injuring nine.

In his book, “The Fourth of May: Killings and Coverups at Kent State,” free-lance journalist and Kent State graduate William Gordon adds his name to the long list of people who have tried to answer why the Guardsmen fired.

The book offers a number of theories, most previously posed, but gives no definitive answers.

Gordon argues strongly that there was some sort of premeditated conspiracy among the Guardsmen. He offers evidence that they planned the attack while huddling on a practice football field moments before the shooting. Other evidence indicates that one or more members of the group gave an order to shoot, though that was never proved in court.

He also argues that an order came down from Nixon or James A. Rhodes, then Ohio’s governor, to make an example of the protesters in an effort to put an end to campus unrest. Again, this theory has never been proved.

But Gordon provides strong evidence including the fact that the Guardsmen all wore gas masks over their faces and tore the name tags off their uniforms, suggesting that they knew what was coming and didn’t want anyone to be able to identify them afterward.

No Guardsmen ever admitted shooting a student and none were ever punished for their actions on May 4, 1970. A civil trial — settled out of court — only netted $675,000 for injured victims and the families of those who died.

The “Fourth of May” is an interesting analysis of what happened at Kent State University that day and of the events that followed. Gordon presents a lot of evidence and documents most of his claims.

But he is also grievously one-sided at times. A student at the time of the shootings, Gordon was actively involved in the struggle that followed to bring Guardsmen to justice. He admits at one point in the book, “I got caught up in the excitement of it all.”

This admitted bias is clear throughout the book. He fails to report the reactions of the Guardsmen or their lawyers after the trials they won. Instead he quotes, at length, the prosecution on why they lost and how they still feel the Guardsmen were murderers.

He also fails to present a clear picture of the student protests. He suggests that a fire at the ROTC building on campus the night before the shootings was started by people planted in the crowds. Looting and near-rioting throughout the town that night before is only briefly mentioned.

After reading the book, I came away with an image of student protests as groups of young people standing quietly and patiently together, holding their middle finger and index finger spread slightly apart, with painted signs next to them that read, “Please don’t send soldiers to Cambodia.”

Whether it was Gordon’s intention to give such a flowery image of student protests is hard to tell, but it unfortunately detracts from the credibility of his arguments.

Thankfully, though, it is the only thing that waters down his arguments. For the most part, the book is convincing, well-documented and well-researched.

In the last chapter Gordon hopes that a Guardsman will come forward and tell the truth about what happened so that a final and definitive chapter can be written.