I assume that since you are asking on this board you are asking about "reliability" in terms of etymology.
I wouldn't consider
Bruce Lansky a particularly reliable source in terms of etymology. On the other hand, he's not as bad as some authors, such as
Diane Stafford, who have a huge number of off-the-wall "meanings" listed.
The books by
Patrick Hanks and his colleagues from Oxford University Press would be among the best readily available paperbacks in English in terms of etymology.