LAST YEAR's Encyclopedia of Jazz in the Seventies described pianist-composer Cecil Taylor as "the avant of the avant garde" - grim and unfriendly praise even if it were true. But Taylor's mature style took shape in the early 1960s; and his subsequent changes, allowing for shifts in his group's personnel, have been minor. Unquestionably he has been an innovator, but the impact of his recordings of the 1960s - arguably less influential than his earlier formative work - has long since been absorbed. It seems sensible to approach him now as an established parallel, rather than as the point of a vanguard.

Three new releases present Taylor since 1969. Indent (Arista-Freedom AL 1038) is the most readily approachable of these. This 1973 solo concert was briefly available from Taylor's own Unit Core company, but most of its original pressing was accidentally destroyed, and it has been a collector's item until now.

Indent, a single three-part work, shows all the essentials of Taylor's pianism. His rhythmic nature has little in common with most jazz; instead, his accents recall Stravinsky's displacements, and the tensions within his phrases reflect and often magnify those within Stravinsky's polyrhythms. Throughout his music - and especially in Indent - these tensions resolve into impressionistic melodies that soar swiftly from key to key, or assert their lyricism against the conflicted tonality of powerful clusters or a fierce hail of descending scales. Textures rarely resemble anything heard elsewhere in jazz piano; rather, Taylor's approach is often truly orchestral: for one example, his tendency to pursue two simultaneous melodies, densely harmonized and deliberately paced, in different registers.

Most feature of Taylor's work lend themselves more to a free development of motives than to the traditional jazz form of repeating choruses; contemporary European vocabulary, though Taylor himself has put much energy into stressing his non-European spontaneity. The spirit and act of improvisation does transform Taylor's materials; not by defusing the tight rhythms, the uncertain tonality, and the bursting textures, but by making them seem less controlled and predictable.

Taylor thus attracts his devotees and zealots with the same force that repels his committed and often unreasoning enemies. Listeners who fall into neither camp must resolve Taylor's strengths - his virtuosic use of the most sophisticated devices, his reservoirs of emotion - with his shortcomings. The obsessive self-absorption implied in Taylor's tersest statement of his artistic creed - "To feel is perhaps the most terrifying thing in this society" - can be a barrier to those who cannot completely identify with a difficult creator. Indent does not present all of Taylor's difficulties, but it may be a good place to begin.

The Great Concert of Cecil Taylor (Prestige P-34003) is altogether tougher stuff. This 1969 concert, once available as an expensive import, presents Taylor's Unit quartet with altoist Jimmy Lyons, Sam Rivers on tenor and soprano saxophone, adn drummer Andrew Cyrille. Given the eshausting force of Taylor alone, even sympathetic listeners may approach this three-record set of group improvising - comprising a single 90-minute composition, Second Act of A, and a twenty-minute encore - with caution. But to balk at Taylor's grand ambitions and inevitable lapses would be to miss his imaginative accompaniments, and the individual contributions of his sidemen. Jimmy Lyons's swinging rhythms contrast with Taylor without contradicting him, and the altoist has grown away from bop cliches towards imitative playing against the piano; while Cyrille uncannily echoes Taylor's rhythms, amplifying the piano's orchestral mass. Further, Taylor's group music stresses his pre-composition - more obvious in ensembles - yet paradoxically, its hectic surfaces speak with a wilder passion than Indent does.

Dark to Themselves (Inner City 3001) is a 1976 concert by a well-rehearsed younger Taylor Unit. With Cyrille out of the group - replaced and largely emulated by the capable Marc Edwards - the focus shifts here to Taylor's more and more empathetic work with Lyons. There are two new soloists - tenorist - whose simplicity of phrasing is welcome, if their pursuit of frenzy seem slightly naive in this company.If Taylor continues to write for them at the level of Dark to Themselves (a single composition, though divided at the end of side one by dubbed "applause" and a fade-out), either or both might easily reach the importance of a Lyons or a Cyrille in the pianist's hyperpersonal musical world.