De infantium aegritudinibus et remediis.

The first printed book dealing exclusively with pediatrics. This was also the first medical treatise, and probably also the first scientific treatise, to make its original appearance in printed form rather than having prior circulation in manuscript. It is also one of the two first books published in print by a living author, the other being Valturio's De re militari (1472). 

The book was based mainly on the writings of Avicenna and Rhazes. It appeared in facsimile in Sudhoff’s Erstlinge (see No. 6355), and there is a translation by H.F. Wright in J. F. Ruhräh’s Pediatrics of the past, 1925 (No.6354). ISTC no. ib00010000. Digital facsimile from the Bayerische StaatsBibliothek at this link.

From the English translation we learn that Bagellardo provided the first description of neonatal resuscitation: "The midwife should examine whether the infant is alive or not, or spotted , that is: whether black or white or of livid color and whether it is breathing or not. If she finds it warm, not black, she should blow into its mouth, if it has no respiration......"

(Thanks to Juan Weiss for pointing out that Bagellardo was the first to describe neonatal resuscitation.)