Bossa Nova was heavily influenced by West Coast Jazz. It blends cool-toned improvising with gentle Brazillian rhythms and melodies.
The exact history of the development is bossa nova not totally clear but it obviously has its root in samba music. The main difference is that Samba is felt in two and has an accentuated second beat while Bossa Novas are felt in four and lack an accent on beat two. You will also notice that that this music has a more subdued feeling than that of the sambas.