CAMBRIDGE — Choptank Odyssey: Celebrating a Great Chesapeake River, the latest book by long time collaborators Tom Horton and Dave Harp, is a vibrant portrait of one of Chesapeake Bay’s most storied rivers. The book of Mr. Harp’s photos and Mr. Horton’s essays depicts the natural history, human history, science and culture of the Delmarva peninsula’s largest river. The authors explored the Choptank — from its beginnings at upstream springs and farm ditches, to its broad estuary below Cambridge — and they celebrate life on the river through the eyes of naturalists, crabbers and crab pickers, oystermen and oyster shuckers, a “turkler” who catches snapping turtles, an ornithologist and a couple of fishermen netting the upper reaches of the Choptank for rockfish. Mr. Horton’s profile of retired biologist and aquatic scientist Nick Carter, to whom the book is dedicated, taps Mr. Carter’s extensive knowledge about the river’s natural systems and what we can do to restore its health. His essay about Harriet Tubman’s Underground Railroad activities in the Poplar Neck area are accompanied by starry landscapes of the area. Tom Horton and Dave Harp have worked together as writer and photographer since they met, while Horton was the environmental writer for the Baltimore Sun and Harp the Sun Magazine photographer in the 1980’s. Since then they have collaborated on countless magazine articles, five books about the Chesapeake Bay, video projects, and most recently with Sandy Cannon Brown on the documentary film, Beautiful Swimmers Revisited. Horton now teaches at Salisbury University and writes commentary for the Chesapeake Bay Journal, where Harp is the staff photographer. The book is available at area book stores, including The Sunnyside Shop in Cambridge and at The News Center in Easton.