Paste Value After Data

I am attempting to copy data from sheet A (macro_sort) and paste value in sheet B (book) at the end of the data in sheet B. I am constantly adding data to sheet B so I need it to paste the new data after the existing data. I have included a copy of the code I am using. Currently it is pasting the data but not by value and not after the existing data; it is wiping out much of the existing data.

Sub book()
Dim a, b As Long
a = Sheets("macro_sort").Range("A" & Rows.Count).End(xlUp).Row
b = Sheets("book").Range("A" & Rows.Count).End(xlUp).Row
Sheets("macro_sort").Range("C4:H" & 5000).Copy Destination:=Sheets("book").Range("B" & b)
End Sub

My macro skills are very very basic so I would appreciate any help in the most simplest of terms.

Thank you
Luke