"[I]t may be my ''midlist'' status (to borrow a publishing term) that best qualifies me to write this book," David Spencer remarks in the introduction to The Musical Theatre Writer''s Survival Guide (Heinemann, 200 pp., $19.95). His rationale for why you''re better off taking advice from someone whose greatest claims to fame are the cult Off-Broadway musical Weird Romance and the English adaptation of La Bohème for the Public Theater''s 1984 production is that, "in an industry that seems sometimes built to defeat anyone foolhardy enough to enter it, I''ve survived steadily -- and most times managed to make my living at it."

Anyone who does that is certainly deserving of respect, but does it really qualify him to write this book? Are more valuable insights gained from those who work steadily but never excel or from those who are recognized time and time again for their unique, outstanding contributions? Your answers to these questions will determine what you take away from The Musical Theatre Writer''s Survival Guide, the content of which is more or less equally divided between the priceless and the useless.

Aspiring authors of musicals will find all of this show-business handbook''s must-have information in the "business" chapters. Spencer offers copious advice on collaborating with co-authors and directors. He explains how to associate and communicate with agents and producers. Perhaps most vitally, he details every aspect of what to do once your musical is written and it''s time to release it to the world. Want surefire tricks for handling readings? Are you interested in recording songs, producing CDs of them yourself, and submitting them to theater companies or competitions at as little expense as possible? Are you confused about the best way to format play scripts? For information on these subjects, you won''t find a better resource.

If you''re seeking advice about writing your show, however, don''t expect Spencer to teach you anything new. Beginning playwriting classes cover the same ground as Spencer''s "Magic Ten" rules of libretto construction. (You need a larger-than-life hero, interesting supporting characters, a character-driven plot, continuous conflict, and so on). A potential lyricist who doesn''t already know that lyrics should relate positively to character, mustn''t tongue-tie the actor, and should rhyme and scan properly most likely has problems that Spencer''s book won''t solve. The author also states emphatically that there''s no such thing as writer''s block and that the most important thing any would-be writer can do is to write musicals for children, because they won''t let you get away with anything.

Indeed, Spencer''s chapter on children''s musicals is nearly twice the length of his chapter on comedy writing. (This is undoubtedly due in no small part to his own success with children''s musicals.) Of the seven pages in the comedy chapter, Spencer uses more than three to discuss and quote from his own work. Yes, there''s also a lengthy quotation of Sheldon Harnick''s "It''s a Fish" from The Apple Tree, but are Spencer''s the only other viable examples? When you factor in all of his personal anecdotes about the problems that he''s overcome as a writer and an 11-page appendix devoted to his work as a theater critic -- including complete reviews of A Funny Thing Happened on the Way to the Forum and Titanic -- it seems that Spencer is most interested in fostering the career of David Spencer.

Even when the book isn''t about him specifically, the author finds ways to express his somewhat myopic viewpoint. One of the unintentional comic highlights is found in chapter four, where he states with apparent sincerity that Pacific Overtures wasn''t fully appreciated when it first opened in 1976 because the TV series Hill Street Blues hadn''t yet prepared mainstream audiences for its fragmented style of storytelling. Spencer''s subsequent argument that a decade of cultural and geopolitical changes paved the way for a better reception for Assassins in 2004 than in 1991 is considerably more persuasive, yet he goes on to express bewilderment, even offense at the inability of these shows to find an audience. He attributes their failure to the fact that they are "group musicals," which he contends are notoriously hard to make work for three reasons: cost, the difficulty of keeping them compelling on an emotional level (Pacific Overtures? Really?), and "the mercy of the times." Apparently, the former''s story about the opening of Japan to the West and the latter''s examination of people who killed or attempted to kill United States presidents aren''t contributing factors.

There are other gaffes in the book. Dismissing Will Parker and Ado Annie as merely comic relief in Oklahoma! suggests little understanding of and/or distaste for that show. (For the record, Mr. Spencer: The leading female character''s name is Laurey, not Laurie.) Choosing not to acknowledge the role that the character Cervantes plays in Man of La Mancha and to instead focus exclusively on the Quixote story greatly oversimplifies that show''s messages. On the plus side, Spencer is brave to question Stephen Sondheim''s disrespect of "hummable" music, and his defense of the existence if not the propagation of the British pop-opera -- or, as he terms it, the "Euro-musical" -- is the most passionate and level-headed that I''ve read.

The book''s most valuable writing insights are the ones that Spencer relates but doesn''t divine himself. Among these: Edward Kleban''s "List of Fifteen," a rundown of 15 possible reasons why a song might not work and, essentially, a master class in songwriting craft; Jonathan Tunick''s classification of clichéd musical buttons at the end of songs; and a lengthy footnote in which Sherman Edwards'' son Keith defends the lyrics that his father wrote for 1776 against charges of careless construction.

What do Kleban, Tunick, and Edwards have in common? They''re not "midlist." Neither are Jeff Marx and Robert Lopez, the songwriters behind the phenomenal success Avenue Q, who studied under Spencer at the BMI Workshop and who penned this book''s foreword. They praise Spencer''s critical abilities, his elocution, his unique turns of phrase ("Your main character is self-pitying, and that''s not your friend"). What they never mention are the musicals he''s written, and this may not be unintentional. What kind of guidebook for aspiring musical authors would Marx and Lopez write? I''m guessing it would be at least as informative and probably more useful to most people than Spencer''s effort.