(1968–1970) Breakthrough

In October 1968, the group had success with a cover of Joe South's "Hush", which reached #4. The song was taken from their debut album Shades of Deep Purple, and they were booked to support Cream on their Goodbye tour.

The band's second album, The Book of Taliesyn (including a cover of Neil Diamond's Kentucky Woman), was released in the United States to coincide with this tour, although it would not be released in their home country until the following year. 1969 saw the release of their third album, Deep Purple, which contained strings and woodwind on one track ("April"). Several influences were in evidence, notably Vanilla Fudge and Lord's classical antecedents such as Bach and Rimsky-Korsakov.

After these three albums and extensive touring in the States, their American record company, Tetragrammaton, went out of business, leaving the band with no money and an uncertain future. (Tetragrammaton's assets were assumed by Warner Bros. Records, who would release Deep Purple's records in the U.S. throughout the 1970's.) Returning to England in early 1969, they recorded a single called "Emmaretta", named for a cast member of the musical Hair, whom Rod Evans was trying to seduce, before Evans and Simper were fired.

The band hunted down singer Ian Gillan from Episode Six, a band that had released several singles in the UK without achieving their big break for commercial success. Six's drummer Mick Underwood - an old comrade of Blackmore's from his Savages days - made the introductions, and bassist Roger Glover tagged along for the initial sessions. Purple persuaded Glover to join full-time; an act that effectively killed Episode Six and gave Underwood a guilt complex that lasted nearly a decade - until Gillan recruited him for his new post-Purple band in the late 1970s.

This created the quintessential Deep Purple "Mark 2" lineup, whose first, inauspicious release was a Greenaway-Cook tune titled "Hallelujah", which flopped.

The band gained some much-needed publicity with the Concerto for Group and Orchestra, a three-movement epic composed by Lord as a solo project and performed by the band at the Royal Albert Hall with the Royal Philharmonic Orchestra, conducted by Malcolm Arnold. Together with Five Bridges by The Nice, it was one of the first collaborations between a rock band and an orchestra, although at the time, certain members of Purple (Blackmore and Gillan especially) were less than happy at the group being tagged as "a group who played with orchestras" when actually what they had in mind was to develop the band into a much tighter, hard-rocking style. Despite this, Lord wrote and the band recorded the Gemini Suite, another orchestra/group collaboration in the same vein, in late 1970.