I only glanced at the book in question in a bookshop, but it was enough to confirm some of the criticisms on Amazon uk.

I think we have already agreed, on a parallel thread to this, that it is highly unlikely that Caesar raised the Tenth in Spain, even if as propraetor he had the authority to do so. In any case Plutarch says he raised 'ten cohorts', nothing about a legion.

According to Suetonius, Caesar's Tenth Equestris was disbanded by Augustus for insolence, though some modern sources suggest that elements of it were incorporated in the Tenth Gemina (Twin), the successor to Equestris, which served (according to OCD) in Spain, Pannonia, and Lower Germany, returning to Pannonia at the beginning of the second century AD.

The Tenth Legion which served in Syria and Judaea, participating in the sieges of Jerusalem and Masada, and was subsequently stationed at Jerusalem before moving to the Red Sea in the second half of the third century AD, was the Tenth Fretensis, which was raised by Octavian in 41-40 BC.