Classical yogic and Vedantic literature does not treat samadhi as a single undifferentiated state but distinguishes multiple grades and kinds, most importantly the broad division between savikalpa samadhi, absorption that retains some subtle distinction or form, and nirvikalpa samadhi, formless absorption in which even that residual distinction disappears, each treated in this atlas as its own doctrine given the weight Advaita Vedanta and later yogic commentary places on the difference. Patanjali's own text further distinguishes samadhi with support, in which the mind still rests on an object, from samadhi without support, in which even that support is transcended, a schema commentators have mapped onto the savikalpa and nirvikalpa distinction with varying degrees of precision.
Because samadhi describes a state reached through disciplined practice rather than a doctrine believed on the basis of scripture or authority alone, textual accounts across traditions converge on describing its effects, including the practitioner's report of altered or absent sense of time, self and ordinary perception, while differing sharply on how the state is best interpreted metaphysically, as contact with the true Self, as absorption into an impersonal Brahman, or as a valuable but ultimately still conditioned state to be gone beyond.