By all accounts I am having a good year. It's only August, but I think it can be declared. I go over the list in my head, holding each memory in my fingers like a sentimentalist's rosary: standing in the dark backstage with Judy Blume, pulling at the hem of a blue dress; the wash of anxiety and relief as I beg for each submission for Syllable; uncountable hours in a pink drawing room with eight-year-old girls; more than one morning spent belly-down in the mud; and, most recently, driving out of Acadia National Park just after dawn.

It is the end of the summer, and I am already feeling the pull of evaluation, of a report card. It's probably the impending fall. How did I do? My brain cries out. Give me a quiz, I tend to say to Greg after a couple of beers. I want to be tested. I want to measure. How many things did I do, how many miles did I run, how many dollars did I save, how many days did I make good use of?

There were many metrics I planned for this year: races to run, pounds to drop, words to write. One thing I did not plan for was this summer visit to Maine. It was a family vacation, the sort where my mother says "this is the plan" and I say, "when are you picking me up?" even though I'm almost thirty and could probably arrange for my own ride. But I don't-- I pack a bag that morning and get washed into the gentle summer tide of family vacations.

I always think of our time together as water-based and cyclical. No Pistell vacation is complete without a swim. On the day of my sister's graduation from Tufts we ditched some formal proceedings and all swam out into Walden Pond in the rain and recited the one line of Thoreau we had memorized. In Key Largo we rented snorkels on a day with no visibility, and on another day with good visibility, and enjoyed both. Most of my teenage summers were spent saying things like "I'm going to swim out to the raft" "I'm coming up on the raft now, watch out," and "it's time to swim back but I'm afraid the water will be cold after spending so much time on the raft." Water days are long and pointless and easy. A part of me wants all days to be water days.

But now, in a family era of strength and robustness and goal-setting and outdoorsiness, all of a sudden we have mountain days. Days when we get up early and ascend. Days where the bliss comes not from collapsing into cold water but from doing something very difficult, and, in my case, frightening.

What I'm trying to say is that this summer, we hiked Mount Katahdin, the highest peak in Maine.

I was nervous about this endeavor. The same group-- my sister Emily, my brother Alex, my cousins Jessica and Jordan-- had gamely agreed to do the Tough Mudder with me in May, which (until Maine) I had pegged as the highlight of my year. (Already evaluated.) I agreed just as fast when they suggested we climb this ancient thing that, as legend would have it, even the Penobscot would not climb because the storm-god Pamola was all over it. If we could do Mudder we could do this! But, as the mountain loomed ever closer, my head began to remind me that the Tough Mudder is all talk. It is man-made, man-controlled, man-marketed. Katahdin does not require marketing or explanation. All that is needed to get a sense of what you're about to do is to suddenly see its black shadow looming over 200,000 acres of preserved forest in Baxter Park. The forest looks wild but the mountain looks wilder still. I have never seen something so still that was so frightening. But then, I knew I had to ascend. I had given my word to my family and to myself.

We camped the night before and got up at 5:45, just as we planned. An hour later we were deep in the woods, moving fast toward the rock slide. The best way to ascend Katahdin is over a rock slide known as the Abol Trail-- the rocks slid down in the 1800's, creating for the first time a rough stairway to the top.

The consequences of this are mostly wonderful. The first mile of trail is flat through the woods, and then you begin to move over the tiny pebbles that have, over 200 years, slid all the way to the bottom of the mountain. As you climb higher, the rocks get bigger. The pebbles become stones and the stones become rocks, and for a couple of miles the rocks are there, getting a bit bigger every few feet. Our feet found new holds with every step, and then, as it became steeper and steeper, our hands had to find holds, too.

The ascent is steep and dramatic, and, since the slide demolished the forest it rolled over, immediately exposed to the sky and the view. No photograph could express how high it immediately felt to me. But, only the day before, we had climbed a tiny and exposed mountain and I had been overtaken by fear, driven upwards only by the shame that I was such a baby.

That height was only 520 feet; Baxter Peak is 5,270 feet. Ten times what, just the day before, had been an extreme, embarrassing, nearly debilitating fear.

Still, I went up towards Baxter Peak. I had planned for it. I had promised myself and my family this mountain.

As those rocks got bigger and looser, I became afraid of so many things. I waited for their steadiness to betray me. I turned back and looked at distance I could potentially fall. (Some would call this a view. I say, a view is only a view if you are nowhere near the edge.) Icarus! Icarus! I called myself. Somewhere in the middle I changed my promise to myself: I would give up. I didn't have to do this. After just a few more steps. Just as soon as I caught up to my family to tell them I was quitting, I would quit. I was driven up by my desire to go down. And then the shame came in like a wind again and I was driven up by the shame of my desire to go down, but I would break my promise to myself and just keep going up.

How many feet, I said to Greg so many times, who had some gadget that measured these things. How many, how much. How many feet have we gone? Even when I wanted to quit, I refused to count down. Even when I was punishing myself for not being in better shape or better spirits, I was counting every foot as a good foot, and not one to be dreaded.

Then, all of a sudden, the rocks became boulders. The top of the slide. Each one seemed bigger than the last and jammed together in such a way that crossing and climbing them required strategy. There was a way over every one, we only had to find it, led by a merciful trailblazing mark. Every strip was our Virgil-- a guide and a warning and a poet of the rocks.

When we got to the boulders, I was happy. Gone were these mid-sized obstacles, endless and loose and ordinary. Give me a boulder, give me a nearness to the top, anytime. And then-- the best thing about this trail-- after three miles of steep ascent, the top of the mountain is nearly flat.

The boulders lay down now, underfoot, unslid. Thoreau says that Katahdin gives the illusion that rocks are a kind of rain. They lie there, covered in moss, by the thousands, a mile in the sky.

And at that point, every step up is a foot climbed nearly to the summit. And you're at Baxter Peak, looking down on Maine, the most beautiful state in the country.

I felt great at the top, of course. There's no better place to congratulate yourself than at the top of a mountain, especially before noon on a clear day. All of a sudden, a view is a view again. You say 5,270 feet, you say three and a half hours. The measurements and the unmeasurable beauty go hand in hand. Just as with the Mudder, and shaking Joan Didion's thin hand, and a hundred great improv shows, I felt here I am in the clear air, uninjured and alive, very alive.

And then, after lingering as long as we could there at the top, even as the fog came in and Emily had to admit it was too dangerous of a day for the Knife's Edge, the inevitable thing happened. We had to go back down.

The boulders became slides, the fog became rain. All the promises I'd made going up had been fulfilled and now, there was no turning back, because the hardest part was the turning back. The moss and the rain and our knees and the waning sun all conspired against us, making everything both slow and urgent. I slid down, I let momentum take me, but not much. My brother Alex and my cousins Jordan hovered silent and protective behind me in the rain, being kind, and my sister Emily and cousin Jessica forged the way forward, being bold and picking out the way for the rest of us. Coming down is harder than going up, every time. It is so easy to forget.

After a while, my siblings and my cousins vanished among the rocks and it was just Greg and I together for the last hour, silently following the blue stripes through the rocks and trees. The gadget died and we no longer checked how many feet we'd gone or how many we had to go. We had done the thing we'd set out to do: reach the top. Now we went to the woods, to see if we could live deliberately. That is, sort of, the line that all Pistells know from Walden.

We reached the woods and walked silently through the last mile, because I hoped to see a moose. I always hope for the big thing. We saw no moose, but the birches hugged us tight in comfort. Greg informed me that the back of my pants had ripped sliding down boulders, and I laughed loudly and likely scared my moose away. At four o'clock, we walked back into camp and put our feet in a stream.

I used to have a lot of water days, even when I did not swim. The days when I drove around New Jersey with my friends for no reason, the days I walked around New York with dogs, the days I read books in the attic: those were water days. Now I have my eye on many personal mountains. I have promised myself small peaks and large.

Katahdin reminded me that every mountain guarantees a descent. What you have measured and achieved will be undone by time. No one lives at the top of mountains, not even ambitious girls who grew up in a town named Summit.

But at the bottom are unmeasurable things: your family, and a place to take off your shoes, and the knowledge that you really did it, no matter how slowly, no matter how immediately it seems like a memory or dream.