Here's a look at the books I've done for general audiences and, below, for young readers.
A Celebration of Heirloom Vegetables is an illustrated introduction to old-time vegetable varieties.  Some are well known favorites, such as Brandywine tomatoes and Moon and Stars watermelon. Others are quirky and bordering on peculiar, and I just felt like growing and painting them.  Entries for each vegetable include basic gardening information and healthful vegetarian recipes that make the most of that crop's distinctive flavor, color, and texture. With 60 recipes and more than 50 watercolors.

--10 by 10 inches, 192 pages

An American Horticultural Society Book of the Year

Available autographed for $30, including postage and handling, from the author.

Children's books
This chubby little book is a handy, fully illustrated guide to 90 varieties. It includes old favorites (Newtown Pippin, Esopus Spitzenburg, Macoun); new favorites (Jonagold, Mutsu, Braeburn, Fuji); and likeable apple oddballs (Knobbed Russet, Pitmaston Pineapple). With recipes for pie, sauce, apple butter, fruit leather, hard cider, and traditional backporch applejack.

--5 by 6 1/2 inches, 255 pages

"[A] handsomely produced volume...  [Yepsen's] watercolors are as appealing as old botanical prints, his descriptions as crisp and lively as a Newtown Pippin."      --American Heritage

Available autographed for $20, hardcover, and $17, paperback, including postage and handling, from the author.
Berries are edible jewels, fragile and all the more precious for it. This book offers advice on finding wild berries and growing your own varieties. Nearly one hundred recipes suggest how to use them in desserts, main dishes, and beverages. Sixty watercolor depict blueberries currants, gooseberries, raspberries, and strawberries, as well as lesser-known gems as checkerberries and wineberries.

--7 by 8 inches, 160 pages

"....[A]n elegant volume...." --The New York Times.

Available autographed for $23, including postage and handling, from the author.  Includes also an erratum slip correcting the blueberry blintz recipe. (The slip is available free and postpaid for anyone who has purchased the book.)

Clockwise from upper left: Cornish Gilliflower, Suncrisp, Ashmead's Kernel, and Fameuse.
Yellow raspberries are a fragile and mild-mannered fruit that seems to embody sunlight. 
Railroaders have come up with their own way of communicating, using colored lights and flags, hand signals, and piercing whistles. Once you learn the railroad's language, even the weediest and wobbliest of tracks will hum with excitement. Illustrated with dozens of line drawings by the author. Published by Pantheon.

-- 6 3/4 by 8 1/2 inches, 85 pages

"Lucidly and in careful detail that never becomes boring, the author explains schedules and tickets, block signals and interlocking signals, lights and horns, flagstops and railroad slang. . . . The book is peppered with fascinating trivia."
-- New York Times Book Review

Urban rail transit was the wave of the future-- until American became dependent on the automobile, allowing thousands of miles of tracks to be ripped up. But trolleys and interurbans are again a hot transportation topic, with a renewed appreciation of their energy efficiency and practicality. They're fun to ride, too, as this book shows in dozens of black-and-white photographs. Published by Macmillan.

--7 1/2 by 9 1/2 inches, 96 pages

 "Yepsen's colorful writing style, alive with clever comparisons, not only helps the many facts go down easily, but also makes reading about what might be considered a routine subject fascinating and fun."
This lively and comprehensive book describes how the human's modest horsepower has been harnessed to propel cars, boats, and planes at impressive speeds and over remarkable distances. Young readers will learn how streamlining, engineering, and lightweight materials now enable humanpowered vehicles to perform better than ever, with the possibility of reducing our need for nonrenewable fuels. There's even a section on how to modify a bicycle to make it go faster. Rare photographs show historic humanpowered feats and flops. Published by Macmillan.

--7 1/2 by 9 1/2 inches, 96 pages

"Yepsen brings together historical material barely touched upon in books dealing with specific kinds of transportation and includes material on recent improvements of HPVs not easily found elsewhere." 
--School Library Journal
-- Why can the mashed potatoes you ate in the cafeteria at lunch make you too sleepy to ace a math test two hours later?

-- How can a good workout in gym make your brain tick more smoothly for the next few hours?

-- Is girls' thinking different from boys'?

We all want to think as clearly and effectively as possible, but many surprisingly common situations can keep us from doing so. Smarten Up! introduces young readers to the impact on the brain of physical exercise, the body's natural clock, nutrition, and even the weather, with tips on helping to enhance or counteract these effects. Published by Little, Brown.

--5 3/4 by 8 1/2 inches, 113 pages

"Filled with anecdotes, tips, experiments, and various odd bits, this is an engagingly chatty survey of the powers of the human brain."  -- Bulletin for the Center of Children's Books
Limited copies of these children's books are available from the author, autographed, for $15, including postage and handling.
If brainy-looking cabbage had a cranium, it'd be plenty scary.  Both green or red varieties can be fermented into tangy sauerkraut, with late-season varieties favored for their sweetness.
These books are available from online sellers, and don't overlook your local independent bookstore, should you be lucky enough to have one.  Autographed copies can be ordered from the author.