Is it legal for a married man to sign the house over to someone else without the wife's knowledge?

If the house is community property, i.e. acquired during marriage (if you live in a community property state), or the couple holds the title as joint tenants, or "husband and wife", then the husband has no tight to sell the house without the wife's knowledge and consent.  Such transfer can be invalidated by the wife even if the purchaser of the house did not know that the wife did not consent to the transfer (i.e. even as against a good faith purchaser).