FULLTEXT search IN BOOLEAN MODE fails - why?

SELECT id, student_first_name, student_last_name, major, minor ,
MATCH(major, minor) AGAINST ('"mechanical engineering"')
AS score
FROM students
WHERE MATCH(major, minor) AGAINST ('"mechanical engineering"' IN
BOOLEAN MODE)
GROUP BY id, student_first_name, student_last_name, major, minor, score
ORDER BY score DESC

This query in MySQL 4.1.12 using MyISAM tables with FULLTEXT index that
maps to student.major, student.minor, produces results that do this:

1) Matches major/minor "Mechanical Engineering"
2) Matches major/minor "Mechanical"
3) Matches major/minor "Mechanic"
4) Matches major/minor "Engineering"
5) Matches major/minor "Engineer"

I was under the impression, according to this MySQL book I have "MySQL
(Third Edition", Paul DuBois, Developer's Library), in Chapter 2, page
197 that if you group your search keyword in double quotes, you will
get only the results within double quotes IN BOOLEAN MODE.

Apparently this is not happening.

Can someone tell me what on earth I did wrong to cause this to happen?

Thanx
Phil