Attributes cannot have attributes, they're attributes not elements
xpather.pl can help you
$ perl xpather.pl ravi06.xml
/book:bookResource/book:book/book:meta/book:title/book:subTitle
# posy
/book:bookResource[1]/book:book[1]/book:meta[1]/book:title[1]/book:sub
+Title[1]
# star
/*[ name() = "book:bookResource" and position() = 1 ]
/*[ name() = "book:book" and position() = 1 ]
/*[ name() = "book:meta" and position() = 1 and @coverImage = "/cover.
+gif" and @doi = "10.1088" and @publicationDate = "
2016-12-01" and @issn = "1111-222X" and @collectionId = "0001" ]
/*[ name() = "book:title" and position() = 1 and @title = "Lattice dyn
+amics" ]
/*[ name() = "book:subTitle" and position() = 1 ]
# rats
/book:bookResource[1]
/book:book[1]
/*[ name() = "book:meta" and position() = 1 and @coverImage = "/cover
+.gif" and @doi = "10.1088" and @publicationDate =
"2016-12-01" and @issn = "1111-222X" and @collectionId = "0001" ]
/*[ name() = "book:title" and position() = 1 and @title = "Lattice dy
+namics" ]
/book:subTitle[1]
# "content"
Book 17
------
/book:bookResource/book:book/book:meta/book:isbn[1]
# posy
/book:bookResource[1]/book:book[1]/book:meta[1]/book:isbn[1]
# star
/*[ name() = "book:bookResource" and position() = 1 ]
/*[ name() = "book:book" and position() = 1 ]
/*[ name() = "book:meta" and position() = 1 and @coverImage = "/cover.
+gif" and @doi = "10.1088" and @publicationDate = "
2016-12-01" and @issn = "1111-222X" and @collectionId = "0001" ]
/*[ name() = "book:isbn" and position() = 1 and @isbn = "979-0-4444-10
+00-17" and @type = "epub" ]
# rats
/book:bookResource[1]
/book:book[1]
/*[ name() = "book:meta" and position() = 1 and @coverImage = "/cover
+.gif" and @doi = "10.1088" and @publicationDate =
"2016-12-01" and @issn = "1111-222X" and @collectionId = "0001" ]
/*[ name() = "book:isbn" and position() = 1 and @isbn = "979-0-4444-1
+000-17" and @type = "epub" ]
# "content"
------
/book:bookResource/book:book/book:meta/book:isbn[2]
# posy
/book:bookResource[1]/book:book[1]/book:meta[1]/book:isbn[2]
# star
/*[ name() = "book:bookResource" and position() = 1 ]
/*[ name() = "book:book" and position() = 1 ]
/*[ name() = "book:meta" and position() = 1 and @coverImage = "/cover.
+gif" and @doi = "10.1088" and @publicationDate = "
2016-12-01" and @issn = "1111-222X" and @collectionId = "0001" ]
/*[ name() = "book:isbn" and position() = 2 and @isbn = "979-0-4444-20
+00-2" and @type = "ppub" ]
# rats
/book:bookResource[1]
/book:book[1]
/*[ name() = "book:meta" and position() = 1 and @coverImage = "/cover
+.gif" and @doi = "10.1088" and @publicationDate =
"2016-12-01" and @issn = "1111-222X" and @collectionId = "0001" ]
/*[ name() = "book:isbn" and position() = 2 and @isbn = "979-0-4444-2
+000-2" and @type = "ppub" ]
# "content"
------
$
$
$
$
$ perl xpather.pl ravi06.xml //*[@isbn]
/book:bookResource/book:book/book:meta/book:isbn[1]
# posy
/book:bookResource[1]/book:book[1]/book:meta[1]/book:isbn[1]
# star
/*[ name() = "book:bookResource" and position() = 1 ]
/*[ name() = "book:book" and position() = 1 ]
/*[ name() = "book:meta" and position() = 1 and @coverImage = "/cover.
+gif" and @doi = "10.1088" and @publicationDate = "
2016-12-01" and @issn = "1111-222X" and @collectionId = "0001" ]
/*[ name() = "book:isbn" and position() = 1 and @isbn = "979-0-4444-10
+00-17" and @type = "epub" ]
# rats
/book:bookResource[1]
/book:book[1]
/*[ name() = "book:meta" and position() = 1 and @coverImage = "/cover
+.gif" and @doi = "10.1088" and @publicationDate =
"2016-12-01" and @issn = "1111-222X" and @collectionId = "0001" ]
/*[ name() = "book:isbn" and position() = 1 and @isbn = "979-0-4444-1
+000-17" and @type = "epub" ]
# "content"
------
/book:bookResource/book:book/book:meta/book:isbn[2]
# posy
/book:bookResource[1]/book:book[1]/book:meta[1]/book:isbn[2]
# star
/*[ name() = "book:bookResource" and position() = 1 ]
/*[ name() = "book:book" and position() = 1 ]
/*[ name() = "book:meta" and position() = 1 and @coverImage = "/cover.
+gif" and @doi = "10.1088" and @publicationDate = "
2016-12-01" and @issn = "1111-222X" and @collectionId = "0001" ]
/*[ name() = "book:isbn" and position() = 2 and @isbn = "979-0-4444-20
+00-2" and @type = "ppub" ]
# rats
/book:bookResource[1]
/book:book[1]
/*[ name() = "book:meta" and position() = 1 and @coverImage = "/cover
+.gif" and @doi = "10.1088" and @publicationDate =
"2016-12-01" and @issn = "1111-222X" and @collectionId = "0001" ]
/*[ name() = "book:isbn" and position() = 2 and @isbn = "979-0-4444-2
+000-2" and @type = "ppub" ]
# "content"
------
$
//*[ name() = "book:isbn" and @isbn and @type = "ppub" ]