Who's the generous one? It's not easy to tell.

I like the idea of being generous. I dutifully offer money to homeless people and a bite of cherry pie to my husband, who decides too late that vegan custard at the local patisserie wasn't the wisest selection. Still, my giving is premeditated, sacrifices assessed. Not until I met teacher and author Sylvia Boorstein did I consider the potential of impulsive generosity.

"Think of giving not as a duty but as a privilege," wrote John D. Rockefeller Jr.

This is the philosophy of Ms. Boorstein, too. She understands how, in cultivating unprompted generosity, we shift our thinking from what we can get to what we can give. After I interviewed her at Spirit Rock Meditation Center in Woodacre, Calif., last winter, she invited me to lunch in the staff yurt.

"Thanks, but my mother's waiting for me in the car," I replied.

Boorstein beamed and said, "She can come, too!"

Five minutes later, Mom and I shared sweet potato falafel that was all the sweeter for the unexpected invitation.

Boorstein described several types of generosity that day. Tentative giving involves the reluctant parting from an object we keep "just in case." Surely, this form of giving has motivated thousands of people to join Freecycle.org, the online sharing network in communities nationwide.

After I signed up, a woman in my city posted this request: "Wanted: Inflatable yoga ball."

My sister had sent me such a ball. But I'm a yogi who likes to keep my feet on the ground. Bouncing blue spheres unsettle me. So the ball gathered dust. Still, I balked at replying to the post. What if I made my peace with the ball? Was it ethical to give away a gift?

In the end, I offered the ball to the woman, who left a grateful note on my porch when she picked it up.

Inspired, I looked around for other unused items. Exercise bands caught my eye. I'd purchased them to work out when I travel, but who thinks about glutes and triceps when exploring Boston or Peru?

I posted the bands on Freecycle, and a grateful businessman claimed them. Next, a spare coat found a home with a college freshman, as did black shorts that flattered in the dressing room - as shorts often do - but not in my own mirror.

My husband, Jonathan, gaped at items on our porch bearing sticky notes with the names of Freecycle recipients. "You're addicted to giving," he said.

Actually, I was determined to unclutter our house. After all, it's easier to give than it is to clean.

Sensing less-than-noble motivation in my generosity, I considered how I might offer "gifts" of intangibles as well. On daily runs, I paused to pet cats and admire neighbors' roses. I drove a friend to the airport, and one day I stifled my impatience when my husband stopped to pick up a cyclist with a flat tire. Exhausted from a backpacking trip, Jonathan nevertheless made a U-turn after passing the cyclist, who was carrying his bike. "Need a ride?" he asked.

The cyclist gaped in surprise. "Thanks, dude! Upholstery tack shredded my tire. Drivers passed me for an hour. You know, in Alaska it's practically illegal not to rescue people. They need each other to survive."

We do need one another to survive. We don't have to live in the land of perpetual snow to grasp that, I've come to realize.

Sometimes, giving can be reciprocal. This isn't to say that we should offer something hoping for reward, but it's inevitable that good deeds return to us.

Last summer I called a nursery for an estimate on manure for the garden. "Three-hundred dollars for cow dung?" I yelped, and sprinted to my computer. "Wanted: Manure," I wrote on Free-cycle. "Must not smell gross."

I received a flurry of e-mails: "I've got a load of sheep manure." "Rabbit manure OK? I've got a truckload, if you've got a truck." "Pick up free horse manure at the stables near River Road."

Our neighbors' generosity astonished me. Jonathan and I tossed a spade into our truck and rumbled toward the horse stables. There, we discovered a 20-foot mound of greenish manure.

"We've hit the mother lode," I whispered.

With one garden spade, filling the truck bed would take hours. In five minutes, we stood slathered in sweat and hay, gazing at the tiny pile in the truck. "I'll borrow something," I said, panting.

In a stable, I spotted a wide, deep shovel. A teenager stood in one stall, raking out what my mother calls "road apples." I approached him: "May I borrow your shovel?"

He squinted. "Why?"

"We're picking up horse manure for our new garden."

"You're what?" he asked incredulously.

He followed me out to the pile. Jonathan stood entrenched in manure. The boy shook his head. "It's my only shovel," he said.

I thought again of Sylvia Boorstein and her teachings on the purest form of generosity. "Royal giving" occurs when givers are so joyful that they offer the best they have. Gandhi practiced such philanthropy, explaining that he always received more than he gave. That day at the stable, I witnessed an extraordinary example of such generosity.

"Anyhow," the boy continued, "that manure's too new. It'll burn your plants. Lemme show you the good stuff."

He led us to a steaming pile of rich compost. "This is what you want." He stared at our appreciative faces and burst out laughing.

"What's so funny?" I demanded. "Don't lots of people drive out here for manure?"

The boy handed me his shovel and tipped his Stetson politely. "No, ma'am, you're the first. Awful generous of you to take it off our hands."