What makes this album amazing, and the reason it is the highest rated rap album ever, is because that not only is Kendrick a great rapper but his music accentuates the ideas he's trying to get across and for me, this isn't an opinion I reserve for Kendrick... it's what I use to measure every rapper by.
When I listen to Jay-Z or Nas or Kool G Rap or with more more contemporary artists when I listen to Blu, Pusha, Kendrick Lamar, Wale, Fashawn etc. I'm judging them by how they use the beat AND their pen, in Kendrick's case he's taken it a step further and hired on some incredibly talented musicians that can bring more to the table than the typical beat maker can. And the cherry on top, Kendrick is literally very involved in the music making process as well...Kendrick isn't just rapping "over a beat", He's crafting music and his voices, melodies, rythms, are part of the instruments.
On average they (the typical beat maker) simply won't know anything about Bebop scales or Altered scales, syncopation and polyrhythms, shifting keys several times throughout a song, writing charts for several instruments or other more complex musical ideas.
I feel this musical ambition once tied to his writing is what makes for a pleasing listening experience.
Like for example when the beat swells on "How Much A Dollar Costs" along with his increasingly frantic flow or how they the hard "Trap drums" seem almost at odds with the sweet and mellow sounding "Seventh Chords" on "Alright" or the dope head nodding hard hitting rhythm and the beat switch on "Institutionalized".
That album is simple pure perfection musically, and Kendrick really pushes the enveloppe as an hip-hop artist by doing things that have never been done, such covering rythmic transitions that never existed in rap, covering the 5 criteria of sentence structures, when nobody else before covered more than 4.
Tpab been analyzed to death, and we could talk about its technical aspects for DAYS...just look at a song like For Free, probably one of the best free jazz songs in the last 15 years. Like for example, when was the last time normal, triadic (3-note) chords were replaced and extended to have lots of notes like that? These extended, spacy chords are reflected all over the album... Jazz has been in rap for a while, as on TCQ songs. But those were always samples. Tpab has successfully produced organic and perfect jazz elements, and like Kamasi Washington (probably the best jazz artist right now) said, TPAB could be considered the best jazz album of the past 15 years, despite being a rap album first.
Tpab, on top of being a great rap album, is a groundbreaking musical album. And some of the songs, as opposed to what been said in this thread, aren't hip hop...so I fail to see how all tracks could be judged as hip hop songs lmao.