A toddler's mother, both an intimate guide and an affectionate coach, writes to a pregnant friend about the transforming experience of motherhood.

These are letters I would have welcomed when I was pregnant, says Beth Ann Fennelly, as she seeks to go beyond the nuts and bolts or sentimentality of other parenting literature. The letters range in tone from serious to sisterly, from light-hearted to downright funny. Some answer specific questions such as decisions about pain medication; others muse about the identity shift a woman encounters when she enters Mommyland or address our responsibility to the natural world. Still others explore the magic and mysteries of childbirth, the wonders of language, and the exhilaration (also the ambivalence) about a baby's first steps to independence.

Here are modern letters written in an old-fashioned way, not as hasty e-mails but more slowly and filtered through the sensibility of a spirited, fearless poet. Though written for a specific person, their themes are universal, inviting all mothers to join the grand circle of giving and receiving advice about children.