This book contains ecological field studies techniques, that can be conducted in wild nature by non-professional researchers - school and university students together with their teachers, single beginning investigators, families, amateurs of all ages. The whole book "Investigating Nature Together" includes 4 parts/series corresponding to a specific season (Autumn-Winter-Spring-Summer) with totally 40 environmental study lessons (see below) covered a wide variety of activities in nature which focus on aquatic ecology, botany, forest ecology, soil studies, landscape analysis, ornithology, anthropogenic effects on nature, etc. Each series contains lessons focusing on practical skills which will be applied in further field studies. The lessons focus on five main themes - landscape, botany, zoology, water ecology and environmental monitoring. Some lessons are closely associated with the seasons and others are more universal. The ecological field study activities address content standards in the areas of earth science, life science, biology, ecology and the nature of science. Intellectual skill development includes questioning, data collection, analysis and drawing conclusions. This book promotes understanding of ecosystems and the protection of the environment through the training of teachers in specific field study techniques, the education of young people in ecology concepts and issues and the sharing of ecological study results between colleagues. The primary goal of this work is connecting students and teachers, addressing important environmental issues and promoting environmental interest, knowledge and values. This book is addressed to the middle and secondary level science teachers and students, and for all those who would like to investigate local wild nature, to share ecological and cultural information and work together to help create a better environment. This specific book "Investigating Nature Together. Part 4: Summer" is the forth in the series. This part involves the most complex studies and relies more extensively on knowledge from previous studies (Autumn-Spring). Many of these activities take advantage of summer conditions such as warmer water temperatures. Practical skills are applied to complex environmental monitoring lessons focusing on streams, rivers, grasslands and forests. The techniques described in this book, were written by Alexander Bogolyubov (1996-2002), translated into English by Tatiana Tatarinova (2002) and edited by Michael Brody (2003). The list of all 40 field study lessons: I. Autumn season: Orientation in the forest Description of Geological Exposure Profiling of River Valley Slope Soil Profile Pit Forest Health of the Coniferous Trees Species Composition and Abundance of Fungi Census of Birds by Line Transect Counting Integrated Study of Landscape Profile Environmental Assessment of Human Impact Assessment of Air Pollution Using Lichens II. Winter season: Making a Fire for Winter Survival Simple Survey of Field Study Site Growth Dynamics of Trees Forest Mapping Green Plants under Snow Cover Territorial Behavior of Titmouse Flocks Winter Route Census of Mammals Mammal Ecology According to Winter Tracking Physical Properties of Natural Waters Snow Cover Profile III. Spring season: Helping Native Birds Early Flowering Plants Spring Flowers Vital State of Coniferous Underbrush Forest Invertebrates-1 Amphibians Rocks and Minerals Daily Bird Song Activity Bird Census Methods Fauna of Vernal Pools IV. Summer season: School Herbarium Flora Inventory Vertical Structure of a Forest Forest Invertebrates-2 Birds Nesting Behavior Comparative Description of Rivers and Streams Aquatic Invertebrates and Environmental Status Plankton in the Littoral Zone Environmental Status of Meadows Status of Forests Based on Asymmetry of Tree Leave