AN ESSENTIAL PROBLEM for the biographer of Theodore Roosevelt is to keep things in due proportion. He was, as Elihu Root understood, alwlays very "hard to hold". To begin with there is so much of him, or more properly, so many of him. He inhabited, by the calculation of Edward Wagenknecht, seven different worlds. Brander Matthews, playing it safe, said he was polygonal. However many sides there are in a polygon, it is obvious that in his time he played many parts, and it is a difficulty to get them all together in orderly composition.

Then there is the larger difficulty. He was, he used to say, a man of ordinary abilities but he usually succeeded in creating extraordinary effects. When he rode to the hounds he came in at the death with a broken arm and a general presence that "looked like the walls of a slaughter house". When he held three thieves in custody on a six-day voyage down an ice strewn river in a small boat he kept a rifle on one knee and a copy of Anna Karenina -which he "read through with great interest"-on the other. When he led the great charge up the hill it almost appeared, as Mr. Dooley said, that he had been "alone in Cuba". And when he proceeded against J.P. Morgan and the Northern Securities Company he seemed to stand, like Christians, steadfast before Mr. Worldly Wiseman and the foul Fiend coming across the field to meet him.

This vivid heightening of every circumstance makes it diffcult to establish the proper correlation of actuality with what may have been mere theater. Was this exaggeration in all things the performance of a pitchman with somewhat less than solid goods to offer, or was it the essential increase in dimension that identifies the authenticated hero? And somewhere amid all the sides of the polygon and between the improbable pitchman and the possible hero was there a believable man?

Fifty years ago Henry F. Pringle, torn between astonishment and vexation, made a good start on this last question in the early chapters of what is still the best, if flawed, assessment of the whole career. Twenty years ago Carleton Outnam in his matchless study got him to the very life but left him, neither finally tested nor fully proved, at the age of 28. In this handsome book, The Rise of Theodore Roosevelt , Edmund Morris extends the arange and pursues his active subject through his first 42 years and to the threshold of the presidency of the United States.

To his task Morris brings imposing assets. He has made himself thoroughly familiar with the large collection of Roosevelt papers (which now includes a remarkable set of revealing diaries) that has been accumulated in the past five decades. He is scrupulous in the use of his material and notably fairminded.In dealing with the problematical personal situations that come before him-father and son, courtship, death of wife and mother on the same day, prolonged disintegration of dissolute, charming and much-loved brother-he never drifts into melodrama or sentimentality but holds things steady. And unlike some of those before him he is neither put off nor confused by the fact that people living 100 years ago had, in the ordering of their lies, to feel, act, and talk like late Victorians and not like us. Then finally, he can tell a very good story. He gets about everything there is to get out of the occasions at his disposal-the college well in the dog cart, the confrontation with a grizzly bear, the aborted duel, the police commissioner's midnight partols, the order to Admiral Dewey and all the picaresque rest of it.

One of the things a biographer of Roosevelt has to do is to set forth clearly the structure of events around the man, to put him firmly in containing contexts and keep him there. New York society, Cabridge, ranching, the state of scholarship when he classified his mammals and wrote his histories. Once these limiting contexts are well defined, Roosevelt, on the rise, can be seen to develop as a part of all that he ahs met-and not just as Theodore, "pure act" taking over, running around and amazing everybody. Carleton Putnam did this very well. Morris not quite as well, but well enough to keep all the diverse attractive forces of the magnetic field in hand. What emerges, or more precisely, bounds from these pages-wheter as son, student, husband, naturalist, historian, cowboy or soldier-is a fascinating and quite beliveable man. It will be a long time before anyone has to go over this particular ground again.

Somewhere within the polygon-indeed at its very center-there is the political animal. In the period covered by this book Roosevelt served his city, state and country in six different offices. Thus there is the opportunity to study the apprentice, if not the fully accomplished master in the art of the possible who has so far eluded complete definition. In this area Morris handles things, as usual, clearly, in a lively fashion, and with fair-mindedness. He also hits all the customary high spots. But here his subject is neither so fully realized nor carefully evaluated. By his reliance on Roosevelt's own reports and on the information and opinions supplied by others who have been there before him. Morris does not take us beyond the received and incomplete impressions. And indeed he seems at time reluctant to do even that. Roosevelt in the governorship of New York-the great school in which he acquired many of the skills of the future president-is given only one third of the attention paid to the cowboy in the West.

This imbalance between the claims of high adventure and those imposed by the daily grind of the public business at secondary levels is, of course, wholly understandable. But the man himself said over and over again that one should prove one's truth by one's endeavor.And he knew, from the beginning, that his own central endeavor, the controlling principle for all his energies, was the conduct of the public business. It is the place to look not only for the man but for the potential hero. Morris, to be sure, gives us a good deal to go on-no doubt some would say enough. But it seems that there is still further work to be done, even here in the early stages, if we are to come to a full understanding of the way in which all the excitement was mixed with the most painstaking dog work to produce the great career. CAPTION: Illustration, No caption, by Edward Sorel