The structure of the album is similar to that of their first, with four original songs and three rearranged covers; however, the tracks are longer, the arrangements more complex and the sound more polished than on Shades of Deep Purple.

Deep Purple's American record label aimed for a hippie audience, which was very influential in the US at the time, but the chart results of the album and singles were not as high as expected.

[10] Moreover, the eight tracks recorded in May for Deep Purple's debut album and performed live in the British gigs of July and August[6] were deemed insufficient for their shows as headliners in the US.

[14] Though the song was written by Diamond, Deep Purple's version musically leans toward the style of Mitch Ryder's recording of "Devil with a Blue Dress On".

"[3][14] On the first of August 1968, Deep Purple entered De Lane Lea Studios in Kingsway, London,[3] with producer Derek Lawrence and sound engineer Brian Aintsworth, who had both worked on their previous album.

[16] Time was granted in larger amount than for the making of Shades of Deep Purple in May, feeding the band’s ambition of coming up with better original material than their previous effort.

[3] On the first song Ian Paice plays a complex drum pattern[17] which sounds like a repeated clash of glass objects, while the second one required a string quartet for the baroque style interlude in the middle.

[3] On 19 August, they concluded these sessions with the recording of "Kentucky Woman" and of the heavy and up-tempo instrumental "Wring That Neck", which came out from a tight collaboration between Blackmore and bass player Nick Simper.

In an attempt to improve sales of the album, a shorter and heavily edited version of "River Deep - Mountain High" was released as a single exclusively in the United States and Canada in February 1969, with "Listen, Learn, Read On" as the B-side.

[37] Besides the original issues, the most significant version of the album is the Remastered CD edition of 2000 by EMI, which contains previously unreleased recordings taken from the sessions of August and December 1968 and from TV shows appearances as bonus tracks.

[11][43] Deep Purple biographer Dave Thompson writes that a dark mood permeates The Book of Taliesyn with little indulgence to pop rock,[40] citing influences of the American band the Doors in the original tracks written for this album.

[40] The influence of keyboard player Jon Lord's classical music upbringing is felt strongly in all the tracks,[17] but this time he was not the main person responsible for songwriting and arrangements, which are considered by critics Deep Purple's first real group effort.

"[20][47] "Anthem" is perhaps the band's deepest venture into classical music on a regular studio album, with its baroque-style interlude reminiscent of a Bach fugue written by Lord and performed using Mellotron and string quartet.

7 and Tchaikovsky's Ouverture-Fantasy "Romeo and Juliet" are in the instrumental intro "Exposition",[19] while "River Deep, Mountain High" is introduced by the notes of "Also sprach Zarathustra", written in 1896 by Richard Strauss and very popular after its inclusion in the film 2001: A Space Odyssey, screened earlier in 1968.

[48] The lyrics written by the band's singer Rod Evans are very functional to the music and the marketing Deep Purple's record label was building up for the American hippie audience.

[40] The notes in particular were written in a mystical tone, evoking the bard Taliesyn as a spiritual guide and comparing listening to the songs to an exploration in the band members' souls.

[50] The original cover was drawn in pen, ink and color by the British illustrator and author John Vernon Lord, who coincidentally appears to share the same name as Deep Purple's keyboard player.

[28][59] After a week of forced stop, their American manager succeeded in setting up a tour which included the San Francisco International Pop Festival[60] and venues on the West Coast.

[59] The tour was a success and Deep Purple's popularity in the US received another boost from a TV appearance at Playboy After Dark alongside Hugh Hefner on 23 October 1968.

[28][58] In late December, the band managers Tony Edwards and John Coletta booked some studio time in New York to record a new single, after the relative failure of "Kentucky Woman" and "River Deep, Mountain High".

[67] Deep Purple debuted the new single "Emmaretta", new material and new takes on songs from their released albums at BBC sessions for the Top Gear radio show on 14 January.

It was at this time that Blackmore and Lord decided to change Deep Purple's musical style, veering towards straight hard rock, which led to Evans and Simper's dismissal in July.

[72] Only the instrumental "Wring That Neck" remained a staple of Deep Purple's performances for a couple of years, working as a frame for Blackmore and Lord's long improvisations[73] and coming back in the set list of the current line-up in the 2000s.

[28] In an interview, Simper tried to explain their lack of success in their home country, saying that the British audience was more interested in a fancy presentation than music and that blues rock "was becoming very big" at the time in England.

Joe Viglione of AllMusic compares Deep Purple's production to Vanilla Fudge's, underlining how the two bands covered songs from the same authors and used similar arrangements.

[41] He writes that on The Book of Taliesyn Deep Purple veered more towards progressive rock than their American counterparts, combining meaningful lyrics and "innovative musical passages".

[41] On the contrary, PopMatters criticizes the "Spinal Tapish" lyrics and the lack of hit material on the album with the exception of "Wring That Neck", considered "perhaps the first real Deep Purple composition.