Young children's curiosity about nature and their need to make sense of the world presents an opportunity to incorporate science as a natural and critical part of children's early learning. This guide, part of a preschool science curriculum, uses an inquiry approach to encourage young naturalists to observe life more closely, build an understanding of what is living and nonliving, and develop science inquiry skills and scientific dispositions. The guide's introduction describes the rationale and curriculum goals, details supportive characteristics of the classroom environment and culture, discusses the fundamental role of play, and offers suggestions for involving families. The remainder of the guide is organized into six sections. Section 1 provides tips for preparing the physical environment. Section 2 presents the open exploration of plants and animals, during which children learn to use basic tools and describe characteristics, behaviors, and needs of living things in their natural environment. Section 3 involves more focused exploration of plants whereby teachers create opportunities for discussion and reflection as children are involved in growing plants, monitoring plant growth, studying plants and their parts, and conducting monthly observations. Section 4 involves more focused exploration of animals as children search for animals, create a terrarium for animal visitors, observe animals and their body parts, and study animal behavior and life cycles. Included throughout these sections are teaching plans and preparation steps. Sidebars provide examples, reminders, and sample teacher notes to illustrate how the curriculum may be implemented effectively. Section 5 presents extension activities to broaden learning experiences through field trips, guest naturalists, and books/videotapes. Section 6 highlights teachers' role in the inquiry process; describes observation, documentation, and assessment procedures; contains instructions for plant and animal care; details suggestions for involving families; and lists recommended books and videotapes. The guide's seven appendices include suggestions for long-term representational projects, guidelines for creating documentation panels, and forms for documenting learning activities and outcomes. (KB)