Suppose you know someone who wants to become Catholic, has fallen away from being an active Catholic, or wants to be inspired to remain Catholic. In that case, this little booklet is for you. Fifteen Letters to Lily is meant to be encouraging while enabling the reader to reason back against anti-Catholic rhetoric. While written to a grandchild from her grandfather, it intends to allow the reader to listen in on the grandfather's presentation to his grandchild. In this way, the reader can embrace the thoughts conveyed and hopefully accept the perspective presented to the reader. The saints' writings elucidate the author's rationale based on Catholic doctrine. The summary letter of Fr. Peter Mary, F.SS.R, a Catholic priest, offers hope and direction. The letters are about various subjects and life issues everyone faces. This book intends to provide some answers to people needing a path back to the true faith of Jesus Christ. The letters are concise to avoid spiritual indigestion and allow the reader to finish all letters while thoroughly considering their contents. This booklet supplies a starting point for family members who may have doubts about their own Catholic beliefs. Upon receiving the Sacrament of Confirmation, Fifteen Letters to Lily provides an appropriate gift for the new soldiers of Jesus Christ.