Described by Garcia as "a definite ode to musical history", the record expands on her jazz roots while incorporating dubstep, reggae, Colombian cumbia, calypso, hip-hop, soul, and African-diasporic sounds.

The album features her touring band members: pianist Joe Armon-Jones, double bassist Daniel Casimir and drummer Sam Jones.

The title track was served as the lead single from the album, and features guest appearances from saxophonist Cassie Kinoshi, trombonist Richie Seivwright, and Colombian band La Perla.

He considered the record as a "stunning introduction" in which Garcia "meditates on her humble family heritage, the continuum of jazz history, and the power of collective action in our present moment.

[11] Thom Jurek of AllMusic lauded the album for its "adventurous, kinetic, and sophisticated approach in wedding modern composition, improvisation, and production to rhythmic and harmonic traditions" and listed it amongst the best jazz records of London.

[12] In The Line of Best Fit, Stephen Loftin wrote that "Source is akin to an old friend you may not see for a while, but whenever you do, the world feels that little bit brighter and it’s as if no time has passed at all.