Ryan H. Walsh's Astral Weeks: A Secret History of 1968 goes deep into the context and events which preceded the recording of the album, now considered to be one of the greatest albums of all time.

Focussing on Van's time in Boston, where he was Irish rock & roll refugee who hadn't yet condensed his talents into a body of work which he could be proud of, the book delves into this brief, but important period of writing.

Walsh's take looks at the underground music scene in Boston, where cult leader Mel Lyman, future rock legend Peter Wolf, Jonathan Richman and even Lou Reed were rubbing shoulders with each other. Walsh even catches up with Morrison's former wife Janet Planet, who tells him, "Being a muse is a thankless job, and the pay is lousy."

In Belfast, Morrison was still wet behind the years and wide-eyed at the success of Them's famous hit, 'Gloria'. But under the tutelage of manager Bert Berns, he came to New York and scored the pop hit 'Brown Eyed Girl' - whose innocent subject matter was undercut by the tough lessons it taught Van about the unforgiving music industry. When Berns died, according to Walsh, Morrison found himself owned by the mob and his new bosses were not sensitive to his creative ambitions. One of them, Carmine "Wassel" DeNoia, explains to Walsh why Van left New York: "I broke his guitar on his head."

So Van fled to Boston, where he met a group of like-minded artists and music lovers who grounded the young Celtic exile. The city, Walsh explains, was a fertile place for Van to explore his deep, poetic musings, and the people became his audience, his co-creators.

Van Morrison has consistently refused to explain the eight songs on the album, often rebuking and confusing interviewers even for asking him about them, so scribes have tried to put their own spin on them for years.