While the association between shared book reading (SBR) and child language development is well documented, there has been less focus on how book characteristics may differentially elicit parents' language input and hence differentially relate to children's language skills during this activity. Moreover, despite the positive and unique role that fathers have been shown to play for children's language, the father-child SBR evidence base is small. Accordingly, the present study examined variation in father and child language quantity, quality, complexity, and function during SBR with text-based and wordless picture books and explored associations between fathers' language and children's language during these episodes. Participants were 46 father-child dyads (20 females). Fathers' mean age was 38.74 years (SD = 5.74), and children's mean age was 37.89 months (SD = 2.71). Findings indicate that fathers in the text-book condition produced significantly greater language quality, extended the topic more, and produced more conversational utterances but described and labeled pictures less than fathers in the wordless picture book condition. Fathers' language during both SBR episodes showed differential links with child's language and may suggest that fathers were fine-tuning their language in accordance with their child's language skills (effect sizes ranged from r = 0.45 to r = 0.78). It is possible that variation in book content may encourage different types of learning with distinct effects on different domains of child language. Should future research replicate such differential relations, findings may inform caretakers and early childhood interventions with the aim of promoting children's books tailored to specific language areas of interest.