Here are two wonderful sports books.

"An Outside Chance," by Tom McGuane, is a collection of essays about outdoor sports -- or at least it starts with outdoor sports: mainly fishing for trout, permit, bonefish, mutton snapper and striped bass; but there are also pieces on motocross, rodeo and a final elegiac memoir on hunting.

"The Sweet Spot in Time," by John Jerome, is about the biomechanics of competitive sports, or athletics. It contains technical appreciation of what it means to be an athlete -- a good athlete or a great athlete; it has some lovely passages of Jerome's sensations at his own efforts over the years; and it has enough exposition of physiological theory to make this book a necessity for any coach. If you have no desire to find out what "aerobic" or "lactic acid tolerance" might mean, this book may present some problems. I'd run into this sort of talk before and was grateful to be brought up to date. Bringing the reader up to date is one of the things Jerome does very well.

There is a chapter on weight-training theories that puts in skeptical perspective all the magic claims of isometrics, isotonics, isokinetic programs and devices. As he does in his chapter on nutrition, or one on aerobic vs. anaerobic training, Jerome weeds out the hype, cautions against the spotty science brought in by the promoters and manufacturers (frequently the truth, but not the whole truth). But Jerome manages to end on a hopeful, encouraging note. His message is that there are benefits from these new theories and gadgets, but that each athlete is so different from any other that no boiler-plate instructions will cover the individual case. Indeed, the book itself, while vastly informative, isn't a specific how-to book. It's rather a methodology -- how to experiment, how to observe, how to look for help from the various experts and how to blend their findings with your own common sense.

The only slight caveat that should be given about "The Sweet Spot in Time" is that the subject of the physiology of athletic performance is surprisingly large, and at the same time surprisingly new -- since most medical science until recently has concentrated on pathology rather than health. The subject, therefore, is both so large and so new that Jerome at times can only point to the future with awe. But it's no great complaint to say that there is room for a sequel in five years, and this book is a masterly compendium of information and reflection about the human body in athletics. It should set a good standard and tone for writing on the subject. a

"An Outside Chance," by Thomas McGuane, is a different order of experience. McGuane is a prose writer (novels, short stories, screenplays) with one of the most seductive styles going. I've run into people who can quote, without book, sentences and whole paragraphs from his novels "The Bushwacked Piano" or "Ninety-Two in the Shade." There are passages in "An Outside Chance" worthy of savoring, if not committing to memory. Here is McGuane in the midst of his essay on the striped bass, the game fish of his pre-adolescent New England days:

"One of my earliest trips to Sakonnet included a tour of The Breakers, the Vanderbilt summer palazzo. My grandmother was with us. Before raising her large family she had been among the child labor force in the Fall River mills, the kind of person who has helped make really fun things like palazzos at Newport possible.

"Safe on first by two generations, I darted around the lugubrious mound, determined to live like that one day. Over the fireplace was an agate only slightly smaller than a fire-hydrant. It was here that I would evaluate the preparation of the bass I had taken under the cliffs by the severest methods: 11-foot Calcutta casting rod and handmade block-tin squid."

For wise-guy self-rebuke, that "safe on first by two generations" is hard to beat.

Eleven of the 18 essays are about pursuing fish and game, and McGuane does two things to the subject. One is easy: He establishes who the jerks are. This is not so much a matter of skill as state of mind.

"What is emphatic in angling is made so by the long silences -- the unproductive periods. For the ardent fisherman, progress is toward the kinds of fishing that are never productive in the sense of the blood riots of the hunting-and-fishing periodicals. Their illusions of continuous action evoke for him, finally, a condition of utter, mortuary boredom. Such an angler will always be inclined to find the gunnysack artists of the heavy kill rather cretinoid, their stringerloads of gaping fish appalling."

But after you subtract the jerks from the anglers you aren't left with heroes. McGuane allows as how fishing can be awkward and feel foolish. He runs into another trout fisherman one day, a painter, as it happened, and they rattle on pleasantly about streams of their past. But -- "Now here, the painter and I were loath to confess we'd moved family, bag and baggage, to Montana for the sake of, well, not even a mammal ."

It is mainly by the implications of his straight prose efforts at the beauty of sky and water, birds and plants -- all that surrounds the fish -- that we get an idea of the invisible grace, the invisible wildness that can be touched by fishing, felt for a short spell.

Almost by the way, these 11 pieces on fishing give a portrait of one fisherman and the life for which fishing is one of the few solaces. In the other pieces we get McGuane from a slightly different angle. There's a very engaging, comic and finally sorrowful narrative called "Roping, from A to B." McGuane is talking about "dally roping" as opposed to "hard-and-fast." Hard-and-fasters tie the lariat to the horn, dismount and tie the cow up. It's what you see on "Wide World of Sports." Dally ropers stay in the saddle and take a turn around the saddle horn. The risk is to the hand holding the rope if it gets in the loop meant for the saddle horn.

"When I first started to rope that way, the lunacy of roping 600-pound Corriente steers . . . without tying the end of the rope to the horn was obviated by the fact that I had misconducted my life to the point that it was, shall we say, in smithereens, and the prospect of losing a couple of fingers because I don't get my wraps didn't seem as catastrophic as it would have when I was happy and had my accustomed, highly excitable fear of pain. This is the background of stoicism everywhere."

I think that's a nice point, expandable, as the man says, to all those other daredevil carryings-on by otherwise sane folks.

There are relatively few books of this kind about outdoor sports -- "The Unnatural Enemy," by Vance Bourjaily, is the only one I can think of that is as complete a fusion of exact enthusiasm and literate reflection -- so it's not enought to say "An Outside Chance" is in the top 10, or even the top two. It's a very savory book, with a healthy maverick disdain for jerks (meat fishermen, developers, the Corps of Engineers), with no special pleading for his own foolishness, and with an expert reckoning of the outdoor pleasures McGuane has found in this republic and in its idiom.