Define your dreams before re-entering the job market; Re-rentering: Successful Back-to-Work Strategies for Women Seeking a Fresh Start , by Eleanor Berman. New York: Crown Publishers Inc. $8.95.

"Re-entering" is an encouraging reference guide for wives and mothers who have decided to rejoin the job market after doing a stint as full-time homemaker. It is aimed at women who are ready to march back to work when the children are in school, or who find themselves needing a job because of divorce or widowhood.

Eleanor Berman offers an outline of steps that women can take in moving back into the work field, as well as a few personal histories of women who have successfully re-entered.

A woman should take a personal inventory, probe to find out whether she is ready to work, look at the skills she hs gained in her role as homemaker, and get reacquainted with herself by redefining old dreams and goals, according to the book. A woman who has taken the time to research why she wants to work again is in far better stead than one who finds herself at a job interview unable to answer questions. One woman discovered how unprepared she was when she went to apply for a job and couldn't even fill out the application properly.

The book outlines ways to check out career possibilities. And Mrs. Berman highly recommends interviewing with experts in a field just for the sake of information, not for a job. Talk to women already on the job and ask them how they got their positions, what sort of advice they would have for a newcomer, and what pitfalls should be avoided.

Women can also capitalize on skills from home. One women sewed all her family's wardrobe while living in Africa where her husband had a diplomatic post. After the family had returned to the US, her divorce meant she had to augment her income. She and another woman came up with teh idea of a sewing business which includes custom dressmaking, alternations, and patterns, as well as classes and consultations on wardrobes.

Colleges and universities recognize the trend of homemakers joining the work force, so many offer courses in career counseling ans skills brush-ups, the author points out. Scholarships for women who want to earn a degree or finish an old one are available.

There is also sound advice on writing resume and cover letters. Equally helpful is a chapter on how to get a foot in the front door of the company after selecting a field of interest. Be specific, Mrs. Berman admonishes. Don't send a cover letter to an anonymous "Personnel Department." USe names and contacts. Follow letters with phone calls.

And be creative. One women got interviews and an eventual job through the stength of an unusual letter of recommendation. She wrote a letter touting the management capabilities of a person with business experience and college training in English. At the end she pointed out that she was writing the recommendation about herself.

The author also includes an appendix with information and addresses on job counseling, career information, educational programs, and financial aid.

Overall, the book paints a picture that seems too rosy. It touches lightly upon the disappointments many women find when they seek jobs after having spent years at home. The age and sex discrimination that women encounter are mentioned only in passing. "Re-entering" neglects to tell women what they can do when they run up against these blockades.

And in writing about what mothers can do with children while they work, the book assumes that most women will be able to find day care or hire baby sitters with ease. Child care ism usually available, but shrugging off the "3 o'clock syndrome" (mothers who think they should be at home when their child arrives from school) as if it were an unrealistic guilt will not answer the anxieties that many families faces when mother goes back to work.

The book passes too lightly over the ambivalence some women feel. A few women mention it in their interviews.

"There is guilt," says Gladys, wife and mother of four children. She enrolled in law school at age 37. "It can't be avoided. I wish I had more time to spend with the children. I recognize the ambivalence in these thoughts, and I have found to my surprise that they are generation. I am torn between my biological reality as a mother and my emotional and intellectual needs."