Neighbor built a deck and blocked my window. No mention of such in their permit. What type of lawyer will I need?

You would want a real estate attorney, preferably one who handles neighbor disputes, property-rights litigation, zoning/land-use, and code enforcement issues.

The key questions are whether the deck violates the permit, setback requirements, zoning rules, building code, HOA/CC&Rs, an easement, or creates a legally actionable nuisance. The fact that the deck was not shown or described in the permit may be important, but the first step is usually to get the complete permit file, approved plans, inspection records, photos, and any survey or property-line information.

You may also want to file a complaint with the local building/code enforcement department so the city or county can determine whether the deck was permitted and built according to approved plans. If the deck is still under construction or the obstruction is significant, you should speak with counsel promptly because the available remedies may depend on timing.

In short: look for a real estate litigation attorney with land-use/code-enforcement experience.

California-specific issue spot: building departments generally enforce state and local building standards, and permits are tied to code compliance. A possible civil theory may involve nuisance, which California defines to include an obstruction to the free use of property that interferes with comfortable enjoyment. But a blocked window/view/light issue is not automatically actionable in California unless there is a code violation, easement, covenant/CC&R, local ordinance, encroachment, safety issue, or other independent legal basis; California cases generally do not recognize an implied right to light and air over adjoining property absent an express grant or covenant.