Borneo to Boston : We find Thoreau's records ; "A self-appointed inspector" ; On thin ice ; Ice at Walden Pond

A hard rain : Nor'easters in New England ; What would Thoreau have done?

Thoreau, scientist : Thoreau as a scientific observer ; Deciphering Thoreau's journals ; Decoding the data ; Our fieldwork begins

Phantom plants : Revolutionary viewpoint ; "Terror" on the tracks ; Pink lady's slipper orchid: a sing of warmer times ; Mercury rising ; Thoreau's mantle passes to Hosmer ; Heat islands ; Plants respond to temperature ; Timing matters ; Thoreau's records and today's climate

Wild apples and other missing flowers : Form common to rare to vanished ; Finding the missing wildflowers ; Vanishing orchids and missing mints ; Species loss and climate change in Concord ; Why do flexible species succeed? ; How fast is Concord losing species? ; Ray Angelo gets mad ; Did we forget about deer?

The strife in loosestrife : The net loss of species ; The McGrath farm ; Any new species? ; Minot Pratt's introductions ; Taking action

The message of the birds : Springtime bird arrivals ; Finding bird arrival data ; Thoreau's birds ; Modern records ; How good are the data? ; What do the bird data show? ; Climate change and many other factors

Birds in the mist (net) : What the Manomet data showed ; How do changes in population size affect bird data? ; Birds and climate: what drives arrival times? ; A farm diary ; Earlier appearance of spring activity ; Putting it all together ; Feathered ghosts

Bees and butterflies : The helpful honeybee ; The forgotten bees ; We shift to butterflies ; Sharon Stitchter's butterfly data ; The great northward expansion ; The Massachusetts Butterfly Club ; Elfins and hairstreaks: a natural experiment

From insects to fish to people : Warming water at Walden ; The value of fishing ; Margaret's approach to fishing ; Eating smaller fish and krill

Clouds of mosquitoes : Mosquitoes and climate change research ; Mosquitoes and Eastern equine encephalitis ; Catching mosquitoes ; Mosquitoes connect birds and people ; Spraying to control mosquitoes ; The importance of insects

The frog chorus : Trouble for turtles ; Too dry or too wet: changing rainfall and amphibian life cycles ; Salamanders in Eastern Massachusetts ; Salamanders in the Hammond Woods ; Salamanders at the golf course ; The future of amphibians in Concord's woods

Running in the sun and rain : Athletic endeavor and climate change ; Does a warming climate affect the Boston Marathon? ; The other side of Heartbreak Hill

A new Earth : An alternative future ; Is climate change really happening in Concord ; The world is changing for the worse ; What do we need to do? ; Can Thoreau show us a better path? ; Living simply in Japan ; Thoreau's advice to modern Americans

Afterword : Citizen science : Getting started ; Joining with others ; My own journal

Appendix : Species mentioned.