Lash's view of E.R.: lonely, heroic; Love, Eleanor: Eleanor Roosevelt and Her Friends, by Joseph P. Lash. New York: Doubleday & Co. 480 pp. $19.95.

Joseph P. Lash is the author of several well-known works on Eleanor Roosevelt , most notably, ''Eleanor and Franklin.'' The first half of this new volume covers much of the ground of that earlier one: Eleanor's childhood relations with her mother and father; her schooling in England under the supervision of Mlle. Souvestre; the courtship of Eleanor and FDR; Franklin's love affair with Lucy Mercer; the years in the White House. The new volume, though, covers these events from a new point of view -- Eleanor's (as candidly or not as she wished) in her letters -- with commentary provided by Lash to fill us in on biographical data and relationships and occasionally offer his personal explanation or interpretation of potentially scandalous or confusing missives.

The commentary comprises the bulk of the book -- the letters figuring more as stones in an intricate setting -- and the effect of commentary, choice of letters, and title is to produce a picture of an individual desperate to bestow love.

Deprived of love and necessary parental attention at an early age, Lash implies, Eleanor Roosevelt never managed to love herself. She sought out the weak, deprived, the sensitive and wounded, the physically and emotionally needy and acted as their supporter and nurturer. This rationale undercuts neither her great goodness nor her untiring efforts toward the improvement of the human lot in general and, in the case of friends and relatives, in particular.

Eleanor emerges from this work as from others, as a lonely heroic figure, striving to lose herself in work for the good of others. Her life and letters show that she felt strongest when others were leaning on her, safe and worthwhile only when in constant demand by the groups and individuals she supported one way or another -- and who thus became rivals for her affection and time.

Occasionally in these letters, I questioned whether her orchestration of clamoring, often jealous, proteges and dependents didn't smack a bit of the manipulative. Also, there seemed a tendency to slip into the martyr's stance in commenting on FDR's conduct and vicarious meddlesomeness in the romances of friends and relations. But these are small faults to find with a character so devoted and adept, not only able to envisage grand designs, but with a genius for organizing their realization. Besides, these are merely my interpretations of the evidence presented; there are others, and this is the book's chief fascination.

The first half of the book is a tantalizing page-turner, with glimpses into the personalities of FDR, Harry Hopkins, Lorena Hickok, Teddy, Alice and Sara Delano Roosevelt, as well as Eleanor and others. Those glimpses and the motives and relations they hint at create, if not a whodunit, a why'dtheydoit: a puzzle of tremendous complexity and, considering the personalities, intrigue.

Another dimension of complexity is added by Lash's comments and explanations of the evidence he offers. Several of these, in particular remarks concerning Eleanor's friendship with Hickok and the reasons for the decline of love in Eleanor's and Franklin's marriage, may strike readers as unconvincing or prejudiced. This is an enthralling document in its demonstration of the ways individuals sublimate, rationalize, or delude themselves in order to preserve and defend their chosen picture of the world.

Lash's candid subjectivity contributes to the interest of the book's first half, but it is the shallow bar on which the second half runs aground. Lash loses his focus on Eleanor at the stage when he enters her life as a young friend. His romance with Trude Pratt, now his wife, assumes center stage.

One wishes the courtship, an up-and-down affair with many hesitations and gnashings of teeth, had proceeded with greater celerity and fewer problems; few subjects excite less interest for others than the day-to-day progress of a troubled love affair. This lapse does not diminish the richness of the book's first half, nor dim the hope that in the second, projected volume of letters, covering the years from 1943 until Eleanor's death, Lash will regain his focus and provide us with more fine close-ups of this magnificent woman.